Since my code works just fine when attaching multiple items from stock Gallery, or file managers (ES Explorer, Solid Explorer, Fx File Manager), I have to assume the bug is in F-Gallery.
Please send me my app's crash log though:
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Crashes are automatically recorded in a crash log, called log-AquaMail-crash.txt and located at the root of your device’s memory card.
Please send it as an attachment to kmansoft / at sign / gmail / dot-com.
This file does not contain any logins or passwords or message text.
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