Thanks for reporting this issue. It has been reported to the developers here: 3.4.1 Paste Into Multiple Tracks Fails · Issue #5594 · audacity/audacity · GitHub
See: After update 3.4.0: Clicking to join clips not working - #2 by LWinterberg
Thanks for reporting this issue. It has been reported to the developers here: 3.4.1 Paste Into Multiple Tracks Fails · Issue #5594 · audacity/audacity · GitHub
See: After update 3.4.0: Clicking to join clips not working - #2 by LWinterberg