shell:
fish, version 3.3.1

os:
ProductName: Mac OS X
ProductVersion: 10.15.7
BuildVersion: 19H1217

TERM:
xterm-256color

if I have a "tall" terminal, when I run history -c foo, if there are fewer entries than lines in my terminal and my pager is set to less, the pager immediately exits.

this is weird, so an example:

$ set -x PAGER less
$ tput lines
28
$ history -c foo | wc -l
      26
$ time history -c foo
________________________________________________________
Executed in   20.90 millis    fish           external
   usr time   20.11 millis   19.03 millis    1.08 millis
   sys time    3.31 millis    1.13 millis    2.18 millis
$ set -x PAGER more
$ time history -c foo
...
<all lines of history -c foo shown>
...
________________________________________________________
Executed in    1.69 secs      fish           external
   usr time   20.05 millis   18.91 millis    1.14 millis
   sys time    3.66 millis    1.34 millis    2.32 millis
$

I'm using omf, but I've confirmed that the behavior exists with omf uninstalled. I've also tried in both iterm and terminal.app

if I make the terminal shorter, like 26 or even 27 lines, then the default PAGER of less works. I've also confirmed that something like,

$ cat <file-with-25-entries> | less

works as well. it's something about the interaction between fish and less that breaks. I don't have an exact version where this seems to have started, but I think this was working in the april timeframe.

Also, this seems to work fine on linux, fish version 3.2.2