Bulk edit doesn't work: 404 error retrieved

Hi!

I have about 4500 product on my site. I need to replace Category name for 1000 products. So I open Products page, click Screen option and set posts to show to 50. Then “check all” -> Bulk Actions -> Edit -> Apply.
Here I set the right category name and click Save.
After long long time I’m receiving 404 error, Page not found. Nothing changed in database.

What I tried:
1. Increasing of max_input_vars up to 13000, memory_limit up to 256 MB, POST size to 105 MB.
2. Deactivating ALL plugins except Woocommerce.
3. Activating default theme.
4. Server reboot
5. WP_DEBUG. There are only errors about “Table ‘wp_postmeta’ is marked as crashed and should be repaired”.
6. Repairing and optimization of MySQL database (it didn’t solve the problem, SOMETIMES the error occurs again).
7. Query plugins shows ~60 slow SQL queries on any woocommerce backend page. Most of them are “update_meta_cache()”.
8. error_reporting(E_ALL); shows no errors at all.
9. Editing .htaccess as said here: http://techsalsa.com/solved-404-error-after-update-or-save-post-in-wordpress/
10. Changing utf8mb4_unicode_ci of wp_postmeta to utf8_unicode_ci.

Have anyone any ideas how to fix this error?

Thanks!

404 Link looks like this:
http://SITENAME/wp-admin/edit.php?s=malaysian&post_status=all&post_type=product&_wpnonce=20637ec1ca&_wp_http_referer=%2Fwp-admin%2Fedit.php%3Fs%3Dmalaysian%26post_status%3Dall%26post_type%3Dproduct%26action%3D-1%26m%3D0%26product_cat%26product_type%26seo_filter%26paged%3D1%26action2%3D-1&action=edit&m=0&product_cat=&product_type=&seo_filter=&paged=1&tax_input%5Bproduct_cat%5D%5B%5D=0&tax_input%5Bproduct_cat%5D%5B%5D=729&comment_status=&_status=-1&tax_input%5Bcharacteristics%5D=&tax_input%5Bproduct_tag%5D=&change_regular_price=&_regular_price=&change_sale_price=&_sale_price=&change_weight=&_weight=&change_dimensions=&_length=&_width=&_height=&_shipping_class=&_visibility=&_featured=&_stock_status=&_manage_stock=&change_stock=&_stock=&_backorders=&_sold_individually=&woocommerce_bulk_edit=1&woocommerce_bulk_edit_nonce=a5dc335764&bulk_edit=Update&post_view=list&screen=edit-product&post%5B%5D=83355&post%5B%5D=82875&post%5B%5D=82675&post%5B%5D=82554&post%5B%5D=82242&post%5B%5D=81997&post%5B%5D=81893&post%5B%5D=81733&post%5B%5D=81685&post%5B%5D=81629&post%5B%5D=81605&post%5B%5D=81581&post%5B%5D=81557&post%5B%5D=81517&post%5B%5D=81469&post%5B%5D=81373&post%5B%5D=81341&post%5B%5D=81317&post%5B%5D=81309&post%5B%5D=81301&post%5B%5D=81293&post%5B%5D=81285&post%5B%5D=81277&post%5B%5D=81229&post%5B%5D=81205&post%5B%5D=81197&post%5B%5D=81189&post%5B%5D=81149&post%5B%5D=81117&post%5B%5D=81077&post%5B%5D=81061&post%5B%5D=81013&post%5B%5D=80997&post%5B%5D=80979&post%5B%5D=80795&post%5B%5D=80723&post%5B%5D=80675&post%5B%5D=80651&post%5B%5D=80611&post%5B%5D=80531&post%5B%5D=80459&post%5B%5D=80420&post%5B%5D=80397&post%5B%5D=80309&post%5B%5D=80277&post%5B%5D=80221&post%5B%5D=80213&post%5B%5D=80205&post%5B%5D=80134&post%5B%5D=80022&action2=-1

Here is my System Report:

### WordPress Environment ###

Home URL: http://SITENAME
Site URL: http://SITENAME
WC Version: 2.6.2
Log Directory Writable: ✔
WP Version: 4.5.3
WP Multisite: –
WP Memory Limit: 256 MB
WP Debug Mode: ✔
WP Cron: ✔
Language: en_US

### Server Environment ###

Server Info: Apache
PHP Version: 5.6.19
PHP Post Max Size: 105 MB
PHP Time Limit: 600
PHP Max Input Vars: 13000
cURL Version: 7.35.0
OpenSSL/1.0.1

SUHOSIN Installed: –
Max Upload Size: 100 MB
Default Timezone is UTC: ✔
fsockopen/cURL: ✔
SoapClient: ✔
DOMDocument: ✔
GZip: ✔
Multibyte String: ✔
Remote Post: ✔
Remote Get: ✔

### Database ###

WC Database Version: 2.6.2
:
woocommerce_sessions: ✔
woocommerce_api_keys: ✔
woocommerce_attribute_taxonomies: ✔
woocommerce_downloadable_product_permissions: ✔
woocommerce_order_items: ✔
woocommerce_order_itemmeta: ✔
woocommerce_tax_rates: ✔
woocommerce_tax_rate_locations: ✔
woocommerce_shipping_zones: ✔
woocommerce_shipping_zone_locations: ✔
woocommerce_shipping_zone_methods: ✔
woocommerce_payment_tokens: ✔
woocommerce_payment_tokenmeta: ✔
MaxMind GeoIP Database: ✔

### Active Plugins (19) ###

Query Monitor: by John Blackbourn – 2.11.1
WooImporter: by Geometrix – 2.2.14
Add Posts to Pages: by Arsham Mirshah – 1.4.1
Advanced Excerpt: by Delicious Brains – 4.2.3
Contact Form 7: by Takayuki Miyoshi – 4.4.2
Content Egg: by keywordrush.com – 2.4.2
Google XML Sitemaps: by Arne Brachhold – 4.0.8
P3 (Plugin Performance Profiler): by GoDaddy.com – 1.5.3.9
WooCommerce Product Filter: by Mihajlovic Nenad – 5.7.3
SEO Friendly Images: by Vladimir Prelovac – 3.0.5
tinyWYM Editor: by Andrew Rickards – 1.2.4
Ultimate Social Media PLUS: by UltimatelySocial – 2.4.6
Video Thumbnails: by Sutherland Boswell – 2.12.1
WooCommerce: by WooThemes – 2.6.2
Yoast SEO: by Team Yoast – 3.3.4
WP Content Copy Protection & No Right Click: by wp-buy – 1.5.0.5
WP Database Backup: by Prashant Walke – 4.2
WP Super Cache: by Automattic – 1.4.8
Youtube Showcase: by eMarket Design – 2.3.0

### Settings ###

Force SSL: –
Currency: USD ($)
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 2

### API ###

API Enabled: ✔

### WC Pages ###

Shop Base: #68321 - /shop
Cart: #83456 - /cart
Checkout: #83458 - /checkout
My Account: #83460 - /my-account

### Taxonomies ###

Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

### Theme ###

Name: GeneratePress
Version: 1.3.31
Author URL: https://tomusborne.com
Child Theme: ❌ – If you're modifying WooCommerce on a parent theme you didn't build personally
then we recommend using a child theme. See: How to create a child theme

WooCommerce Support: ✔

### Templates ###

Overrides: –

https://ww.wp.xz.cn/plugins/woocommerce/