WooCommerce not translated

there are two languages on my site – uk and ru_RU

Language switcher works and content is translated (Menus, pages, products) but woocommerce pages are still in english (cart, checkout)

How to reproduce:
Update WC from 3.5.x to 3.6.x
Downgrade to WC 3.5.8 (Rollback plugin)
Deactivate Hyyan for WooCommerce
Deactivate Polylang
Deactivate and remove woocommerce
Reinstall and activate WooCommerce
Activate Polylang and Hyyan Plugin
after some time woocommerce switches back to english

All language files are present

PS: I played around with PO files because there are some differences in file mats, like
# Translation of Plugins – WooCommerce – Stable (latest release) in Ukrainian
# This file is distributed under the same license as the Plugins – WooCommerce – Stable (latest release) package.
msgid “”
msgstr “”
“Project-Id-Version: Plugins – WooCommerce 3.5.8\n”
“Report-Msgid-Bugs-To: https://github.com/woocommerce/woocommerce/issues\n”
“POT-Creation-Date: 2019-04-16 12:41:03+00:00\n”
“PO-Revision-Date: 2019-05-31 09:12+0300\n”
“Last-Translator: \n”
“Language-Team: \n”
“Language: uk\n”
“MIME-Version: 1.0\n”
“Content-Type: text/plain; charset=UTF-8\n”
“Content-Transfer-Encoding: 8bit\n”
“Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2);\n”
“X-Generator: Poedit 2.2.3\n”

WooCommerce 3.6 PO-file

# Translation of Plugins – WooCommerce – Stable (latest release) in Ukrainian
# This file is distributed under the same license as the Plugins – WooCommerce – Stable (latest release) package.
msgid “”
msgstr “”
“Project-Id-Version: Plugins – WooCommerce – Stable (latest release)\n”
“Report-Msgid-Bugs-To: https://github.com/woocommerce/woocommerce/issues\n”
“POT-Creation-Date: 2019-04-16 12:41:03+00:00\n”
“PO-Revision-Date: 2019-05-31 07:52+0300\n”
“Last-Translator: \n”
“Language-Team: \n”
“Language: uk_UA\n”
“MIME-Version: 1.0\n”
“Content-Type: text/plain; charset=UTF-8\n”
“Content-Transfer-Encoding: 8bit\n”
“Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n”
“%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2);\n”
“X-Generator: Poedit 2.2.3\n”

### WordPress Environment ###

Home URL: https://donutsbar.com.ua
Site URL: https://donutsbar.com.ua
WC Version: 3.5.8
Log Directory Writable: ✔
WP Version: 5.2.1
WP Multisite: –
WP Memory Limit: 256 MB
WP Debug Mode: –
WP Cron: ✔
Language: uk
External object cache: –

### Server Environment ###

Server Info: Apache
PHP Version: 7.2.18
PHP Post Max Size: 50 MB
PHP Time Limit: 30
PHP Max Input Vars: 1000
cURL Version: 7.53.1
NSS/3.28.1

SUHOSIN Installed: –
MySQL Version: 5.7.16-10-log
Max Upload Size: 50 MB
Default Timezone is UTC: ✔
fsockopen/cURL: ✔
SoapClient: ✔
DOMDocument: ✔
GZip: ✔
Multibyte String: ✔
Remote Post: ✔
Remote Get: ✔

### Database ###

WC Database Version: 3.5.8

### Post Type Counts ###

attachment: 80
blocks: 7
customize_changeset: 6
custom_css: 1
flamingo_contact: 3
nav_menu_item: 11
page: 29
polylang_mo: 2
post: 3
product: 58
revision: 132
scheduled-action: 14
shop_order: 66
wpcf7_contact_form: 4

### Security ###

Secure connection (HTTPS): ✔
Hide errors from visitors: ✔

### Active Plugins (16) ###

Polylang: by Frédéric Demarle – 2.5.4
Classic Editor: by Учасники розробки WordPress – 1.5
Clean Image Filenames: by Upperdog – 1.2.1
Contact Form 7: by Takayuki Miyoshi – 5.1.3
Disable Author Pages: by LittleBizzy – 1.1.0
Disable Emojis: by LittleBizzy – 1.2.0
Disable XML-RPC: by LittleBizzy – 1.1.0
Google Tag Manager for WordPress: by Thomas Geiger – 1.9.2
EWWW Image Optimizer: by Exactly WWW – 4.7.4
Force HTTPS: by LittleBizzy – 1.2.0
WooCommerce Simple LiqPay: by Alex Shandor – 1.7 – Not tested with the active version of WooCommerce
Hyyan WooCommerce Polylang Integration: by Hyyan Abo Fakher – 1.3.0
WooCommerce: by Automattic – 3.5.8 – 3.6.4 is available
Yoast SEO: by Team Yoast – 11.2.1
WP Rollback: by Impress.org – 1.6
WP Translitera: by Evgen Yurchenko – p1.2.5

### Settings ###

API Enabled: ✔
Force SSL: –
Currency: UAH (грн)
Currency Position: right_space
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 0
Taxonomies: Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

### WC Pages ###

Shop base: #22 – /shop/
Cart: #23 – /cart/
Checkout: #24 – /checkout/
My account: #25 – /my-account/
Terms and conditions: ❌ Page not set

### Theme ###

Name: Flatsome Child
Version: 3.0
Author URL:
Child Theme: ✔
Parent Theme Name: Flatsome
Parent Theme Version: 3.8.3
Parent Theme Author URL: http://www.uxthemes.com/
WooCommerce Support: ✔

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