Searching items only works for inbox OR other folders

Hello!

I’m currently using WebApp 3.4.21.1690+961.1 on kopano core 8.5.81. I tried searching my mails for certain keywords leaving the settings at the default “all folders”. I noticed that all mails from sent objects and also relevant calendar items were found, but there were no results from the inbox. I only got those when I changed the search settings specifically to “inbox” - then, of course, none of the previous results.
Is this an error or can I do something about it?

Greetings,
Andreas

…strange, all of a sudden it works - problem magically solved.