"Update temporary item data" reverts when page refreshed

HI,
I have a fresh install of Flexicontent 4.1.3, on a PHP8.1, with Joomla 4.2.5.

The issue has started within a few hours, when I could see the dashboard and other menu items just fine.

Things I've tried:
- clicked the "Update", which turns red dash icon to green tick item, but reverts back when "refresh" link clicked or manual page refresh, reverts back without progressing to Dashboard etc.
- manually truncated table #__flexicontent_items_tmp (no change)
- cleared cache, browser cache, joomla cache clear, etc

Things I have noticed:
- database collation on fresh install is MyIASM for that table, my assumption is that a collation should be set, and should be InnoDB engine.
- attempting a change of collation or engine renders error...
e.g.
```Executing:
ALTER TABLE `dbname`.`prefix_flexicontent_items_tmp` 
ENGINE = InnoDB ;

Operation failed: There was an error while applying the SQL script to the database.
ERROR 1292: Incorrect datetime value: '0000-00-00 00:00:00' for column 'publish_down' at row 1
SQL Statement:
ALTER TABLE `dbname`.`prefix_flexicontent_items_tmp` 
ENGINE = InnoDB
```

I urgently need some advice on how to get past the issue to show the Dashboard again, as we are using this tool in an enterprise environment (local gov). We are using the workflow mechanism so that editors need to have items/article changes approved by an admin etc.

Some extra context. We recently upgraded the website from Joomla 3 (latest) to Joomla 4. We trialled the Workflow tool but functionality wasn't complete enough for contributors re-editing content. We have used Flexicontent for the best part of the last 5 years.

Happy to upgrade to premium if needed. Would prefer more one-on-one with core Flexi devs if you need access to help triage the issue as this is a live government website.

Kindest regards,
Noel Dixon (Noxidsoft)
 

For context I've attached a screenshot 

 

hello about this message we works on it
about wokflow can you explain more ? you mean about joomla 4 workflow or flexicontent option ?

@micker Ah, yes I meant about Joomla 4 native Workflow tool, just ignore I said that.

Thank you for looking into this issue. It is quite urgent, as our staff can't approve article changes or new articles at the moment. But, thank you so very much for working on this.

Kind regards,

@micker Do you think it would be detrimental to the extension on our Joomla 4 instance, if I change the database collation and engine?

Would such a change be reverted with the next patch?

Is there any other immediate fix I can try, or patch you might have in the works that I can test for the team?

Kind regards,

hello for now we have some problem to reproduce this error .. we didn't have any patch
yes maybe you can change collation just do a backup before) ...
for exemple here :  flexidemo.com3elles.com/ all sites are in j3 update to flexicontent 4 and we migrate to joomla4 without problem
... very strange return