It's about time

[utu]

In looking for a refinement of the lxpanel digital clock
format to get '01:35pm' to read '1:35pm', I found some-
thing more immediately interesting:

I found someone other than myself whose digital clock is
(or was) one minute (or so) off. My GE stove is keeping
better time.

https://bbs.archlinux.org/viewtopic.php?id=109328

It's not clear (to me) if the 'archlinix bug fix' is
available through Synaptic as yet. I am presuming it is
contained in lxpanel itself and not some another element.

[utu]

Back now to the format question.

You have to look close:
The format %I:%M%P gives times like 02:15pm.

What you want is probably:
The format %l:%M%P which gives times like 2:15pm.

That's lower-case l (small ell, not capital eye), not upper-case i.