Nix-index gobbles memory then logs me off

[MaxwellDupre]

I type in a shell
`nix-index

• querying available packages

Then it just sits there and from the system monitor I see it starts at 20% of memory and slowly it eats the memory and as it approaches 100% it logs me off. I've tried this a few times and I get the same result each time.
I don't see any debug or tracing from the options.
My system is
Linux .. 6.6.30-rt30 #1-NixOS SMP PREEMPT_RT Thu May 2 14:32:50 UTC 2024 x86_64 GNU/Linux
and
25.11.6495.e764fc9a4058 (Xantusia)