Major problem? I think it would depend on where and how large the lam was. I've considered them "cool" especially on nickels, but that's just me.
Short answer: it depends. Long answer: There are a lot of variables that go into this. While a lamination is technically a mint error, many TPGs don't label minor laminations. A minor lamination in a less focal area is fairly neutral; a minor lamination in a focal area is often considered a negative. A major lamination (large enough to be designated as a major mint error) can bring a premium for the error. And, as with everything, some people like them and some people hate them. It's all down to what you like. I personally don't like them, so I avoid them. However, I do own a couple of coins with minor planchet flaws - the rest of the coin is special enough that I'm willing to overlook the lamination. So, in order to give you a good answer, we'd need to see pictures of the coin in question.
Here's an example I'm willing to overlook. The coin is graded NGC MS-64PL - and you don't find PL Flying Eagle's very often at all. However, there's a small lamination or planchet flaw right under the 1 of the date. Many people would miss it unless I pointed it out. This small lamination, in a less focal area, is forgivable when the rest of the coin is superb.
IMO, it is a disservice to a buyer if the label on that coin is just MS-64. The label should say MS-64, Lamination.
Am I missing something or is the obverse also clashed? It looks, from my vantage point like the die was worked on.
Flattening in the letters of Liberty. Appears to be a gouge in the N in Cents and something going on at EPU. Also die polishing going on.
The coin is a commercial MS. It is slightly weakly struck. Outlines from a die clash are visible on both sides (under "Pluribus" on the reverse) and the lamination is on the reverse.
I have no idea what the coin is worth. To me it is an expensive coin with a Mint error ("White Elephant"). A collector would want a better looking coin and a Mint error collector would not pay so much for a common error found on Buffalo nickels. Edit: Looks like it is priced between AU-50 and MS-60.
While that is a lower price than average, you have to answer the following question for yourself: Is the discount worth the problem? For some collectors, the chance to own a reasonably scarce coin in a good grade is worth accepting the problem. However, if you're trying to complete a set, the price of this one does start to become attractive even despite the problem. For some collectors, its worth it to spend a bit extra, or be patient, for a coin that doesn't have the problem. I know which one I would choose (in my opinion, that lamination is too severe for me to want the coin). Only you can decide for yourself. Be aware, however, that if it ever comes time to sell, this coin is going to be harder to sell (and will sell at a discount).
Here's how the market responded to a 1921S PCGS MS-64 with a lamination. $1200 at a time when the average price was $2700: https://coins.ha.com/itm/buffalo-ni...2-3284.s?ic4=ListView-ShortDescription-071515