Post editor custom taxonomy meta boxes broken

Hi,

I have custom taxonomies (hierarchical) created using the WCK plugin. I have been using Polylang along with WCK without incident for over 2 years now.

However when I upgraded Polylang to thr latest version 1.7.8 and WCK to the latest 1.1.6, some of my custom taxonomy meta boxes in the post editor stopped working. When I deactivate Polylang, the boxes start working again as they should.

What happens exactly is that either
1. no terms show for some taxonomies meta boxes,
2. just one of the terms show up in the meta boxes,
3. all the terms show up for certain taxonomies.

Can you help please? I tried downgrading both Polylang and WCK to many older versions but it doesn’t help one bit.

Info:
– I am using a static front page (Genesis theme with Dynamik Web Builder)
– Permalinks structure is /%category%/%postname%/

Example of Settings for taxonomy that is completely broken – no terms show in meta box at all:
Taxonomy:song-writer
Singular Label:Song Writer
Plural Label:Song Writers
Attach to:post, page
Hierarchical:true
Public:true
Show UI:true
Show Tagcloud:true
Show Admin Column: false

Options set in Polylang:
Remove /language/ in pretty permalinks – selected
When the front page is visited, set the language according to the browser preference – selected
Activate languages and translations for media – selected
– Settings: The language is set from content – selected

Thanks

https://ww.wp.xz.cn/plugins/wck-custom-fields-and-custom-post-types-creator/