There are pundits who really don't like it if people call them "pundents." As a listener pointed out to us, this mispronunciation isn't uncommon.
Susan Serafin Jess says, "The otherwise fastidious Jim Lehrer said ['pundent' for 'pundit'] throughout his tenure on the PBS News Hour. I have heard other journalists misuse this, including on WUOM."
Certainly, there are others who have strong feelings about the correct pronunciation of "pundit." Daniel Pinkwater had this to say on NPR's All Things Considered:
"I am not a language snob. I hate those people who constantly correct my speech. But look, some things just shouldn't be. It's 'pundit' not 'pundent.' English is getting dumber, we are getting dumber, but at least resist a little. Why should you listen to me? Because I am well-respected pundit."
In its original Sanskrit, a "pundit" was a Hindu priest or teacher. It showed up in English in 1661 to refer to a learned or wise person in colonial India. The Oxford English Dictionary has examples that show by 1816, "pundit" could be used to refer to an expert in any field, especially one frequently called upon to give their opinion to the public.
Some usage guides and dictionaries note that "pundit" is sometimes used sarcastically. This seems to be particularly true of its verb form. For example, you'll find things like "the pundits were punditing" or "he was punditing his head off."
In terms of pronunciation, many speakers do add an "n" to the end of "pundit." Our listener Susan wondered if perhaps they're thinking of "pungent." That could certainly be part of the picture.
There are a lot of words in English that end with an unstressed vowel + "nt," including pendant, cogent, decent, adamant, etc. It's not hard to see why speakers would add an "n" to "pundit," so it sounds like other words in English.