acl - create item - suddenly "Warning: You are not authorized to execute this task"

Permissions of "Joomla article manager" in both cases look good. Please see attached screenshot.

Hello

Questions

1. Is the message shown after clicking item form save ? , then it could be due to a 3rd party plugin doing ACL checks

2. If you edit the category of the item , then w check

3. do you have a test that i can do tests, or can you provide copy of the website ?

1) No, the message "Warning You are not authorized to execute this task."
is shown on page-load (not on save) of the events:
- list items (of any type, also listing of all items)

The message is not shown is not shown on these events (e.g.):
- create content item (e.g. /administrator/index.php?option=com_flexicontent&controller=items&task=items.add&typeid=2&maincat=. Content Item is saved.

2) >> edit the category of the item , then w check
Do you mean by that: ~"open, cat, save cat, check agein"?

3) Yes, I'd be happy to provide you with BE-access for both live websites via PM.
But maybe it's enough -with above info- for you to put me in a position where i fix the problem?

Thanks!

ok, I think, I fixed it, doing two things:
1) unbelievable but true: clear all backend-caches.
fixed all but one follow-up-error: "Call to a member function isSite() on null" on "list categories" with Setup Joomla 3.9.1 / php 7.2 / FC ~Dev-Preview 3.?? (had gotten a direct link from you in a previous thread).
2) fixed that follow-up-error by downgrading from above now unknown FC-version back to FC 3.2.1.15

ok, now we have a new error:

the post-upgrade-installations-screen keeps returning.
it has one task, and that one task is not directly fixable by clicking.
the task is ~ "indexes in db..."

[setup-details]
the website in question has this flexicontent-install-history
3.2.1.14 ->
3.3.0-rc1 ->
3.3.0-rdev2 ->
3.2.1.15 (I downgraded)

[question]
Ho can I get rid of the returning post-upgrade-installations-screen?

[reproduce]
1) try to visit backend -> items-list e.g.
2) screen appears
3) click "fix"
-> task does not disappear
4) click "REFRESH"
-> screen does not disappear
5) go to backend-start-page
6) go where I wanted to go initially. -> ll ok now.

but the situation returns once a day or so.

Thanks for looking into this!

Hello

hhmm,
the DB-update message will appear once every time that you re-login to the backend

because 3.3.0 has creating in the templates table
i need to give you a query to drop the new primary key (a new integer "id" column)