After days of testing and searching the net it seems this line:
is causing all the troubles with the IM function. There are several questions on developers forums (dated 2016!) with no reply from Xamarin/Microsoft.
While this line works in map-chat and group-chat it DOESN´T work for IMs ….
To show how tricky it is for developers to find bugs they cannot reproduce. This is the bug report with the only hints whats wrong:
0 CoreFoundation 0x18420f164 __exceptionPreprocess + 124 (NSException.m:166)0 CoreFoundation 0x18420f164 __exceptionPreprocess + 124 (NSException.m:166)1 libobjc.A.dylib 0x183458528 objc_exception_throw + 56 (objc-exception.mm:521)2 Foundation 0x184d2baa4 -[NSLayoutConstraintParser failWithDescription:] + 252 (NSLayoutConstraint.m:2932)3 Foundation 0x184b52934 -[NSLayoutConstraintParser parse] + 420
Of course there is no explanation where in 1000s of lines of code the bug happens and why it happens.
Even more weird is that this bug only affects a small part of the MetaChat users.
Thanks all for using MetaChat and thanks for your patience if you got hit by that.