vim hangs (slows) intermittently in mlterm on some UTF8 files

[Mayuresh <mayuresh%acm.org@localhost>]

I connect to a server running NetBSD 9.2 amd64 using mlterm on Void Linux
over ssh.

Sometimes when a file with UTF-8 characters is opened in vim on this
setup, vim hangs for several seconds, often about a minute and then
resumes.

The behavior is not necessarily reproducible on the same file immediately
again but does occur annoyingly frequently.

So I created a NetBSD VM on the client side and launched mlterm from it.
But this problem doesn't occur in that.

In both the cases LANG=en_US.UTF-8 is set on both the client and the
server side.

Then I built mlterm using same pkgsrc options on Void Linux, to rule out
any build differences causing this. But the problem does occur on this
mlterm build as well.

I find this intriguing and thought of sharing and seeking help. Would
appreciate help.

-- 
Mayuresh