Bug#921266: Same crash with linphone 4.1.1 (flatpak)

[Alf]

I just tried to setup linphone in Buster by installing flatpak and the
latest version of linphone 4.1.1. Installation went smooth and it starts
without any configuration (alltogether roughly ½ GB of disk space).

However trying to configure my SIP-account results in the same (or very
similar) crash and segfault when password is entered:

tux kernel: [ 4866.131680] linphone[6107]: segfault at 0 ip
0000003153a8f37a sp 00007ffe572604c8 error 4 in
libc-2.24.so[3153a00000+194000]
Mar  3 18:17:33 tux kernel: [ 4866.131690] Code: 89 e6 5b 4c 89 ef 5d 41
5c 41 5d e9 e0 49 ff ff 89 f8 31 d2 66 0f ef ff 09 f0 25 ff 0f 00 00 3d
c0 0f 00 00 0f 8f 78 02 00 00 <f3> 0f 6f 0f f3 0f 6f 06 66 0f 74 c1 66
0f da c1 66 0f ef c9 66 0f

So my conclusion is that this problem is more general and probably
related to some function/configuration in the Debian system?

Desktop environment is XFCE4.
Remark: my SIP-account (Telekom) requires for registration 2
authentication cycles to register and thus to supply the password twice.