Truncated TCP ?

[J Doe]

Hello,

I run BIND 9.18.26 as a recursive, validating resolver.  In my logs, I
noticed the following:

     01-May-2024 00:52:49.689 lame-servers: info: truncated TCP response
         resolving 'www.ipfire.org/A/IN': 74.113.60.134#53

I am aware that there are issues with DNS UDP traffic being truncated
and/or rejected via firewalls or middle-boxes that enforce limits on
expected packet size (I believe one of the goals of a recent Flag Day
was to address these configs), but what would lead to truncated TCP
traffic in the context of DNS ?

Thanks,

- J