After investigation I found, that this is because of a fixed SOCKSPORT and and fixed CONTROLPORT.
But each user needs his own SOCKSPORT and CONTROLPORT.
To fix this, the upstream script which is installed at ~/.local/share/torbrowser/tbb/x86_64/tor-browser_de/Browser/start-tor-browser has to be changed for each user. The patch is attached.
The patch first searches for free ports and then modifies the config files to use the free ports.
I have build a wrapper script for torbrowser-launcher to apply the patch, if it isn't already applied.
But I hope it will be fixed by upstream.
binTV19DbG2gB.bin
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