8.6.170 crashing on punch-in

im trying to create a bug report for the following problem:
Adding a punch in/out to the range ruler, then pressing 8 to activate punch in/out crashes ardour.
This happens in new sessions with no plugins
I opened a terminal to run a debug session and arrowed up to an existing command, then edited the ardour version number (which was previously something like 8.1.101)
This was the output:
$ sh /opt/Ardour-8.6.170-dbg/bin/ardour8 --gdb
GNU gdb (Debian 10.1-1.7)
Copyright (C) 2021 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type “show copying” and “show warranty” for details.
This GDB was configured as “x86_64-linux-gnu”.
Type “show configuration” for configuration details.
For bug reporting instructions, please see:
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For help, type “help”.
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Reading symbols from env…
(No debugging symbols found in env)
Signal Stop Print Pass to program Description
SIG32 No No Yes Real-time event 32

What does this mean and how to rectify it?
Many thanks
PS Ardour 8 has been great for me, Ive hardly had any problems for a while.