Ok.
(unlikely) Someone else got these types of errors recently and in that case the errors happened because Servoy was being run from source (public sources on github) and a couple of projects needed the .ts files in two projects to be recompiled manually after pulling from Git. Just mentioned that to get it out of the way. I suppose you are running directly from a Servoy install so it does not affect you.
That being said, if you have custom tab-panels it is possible that the out-of-sync I was talking about happens if the tab-panel component shows a form - so it is present in the browser DOM but tells the server that that form was hidden. So any sequence of events that would lead to this situation can result in such messages in the log. Then anything that happens on that form that is present in the DOM on the browser - anything that needs to talk to the server will be denied on the server based on visibility.
In order to debug, you have to follow what that custom tab-panel does with svyServoyApi.formWillShow, svyServoyApi.hideForm and svyServoyApi.getFormUrl, and also see what the browser trying to do that is denied - and when - compared to the svyServoyApi calls.
To follow easier what the browser wants to do when it gets denied, you can - in browser console - enable more detailed Servoy logging:
____logProvider.debugEnabled(true)
____logProvider.debugLevel(____logProvider.SPAM) // for even more detailed logging
Make sure you switch the browser console to "verbose" logging level.
If that is not enough, to follow the svyServoyApi usage add some logging statements (either directly in the js or using conditional breakpoints) in the custom tab panel - it might be initially faster then using breakpoints.
It might be necessary to monitor the denied form's visibility on server-side as well. See when that form is shown/hidden in the solution compared to the above.
Any very complex scenarios in my head that might explain this I am trying to ignore
. You just have to debug what's really happening.