Can a t-stat fail and be partially open?

Back story: last weekend I went to the dunes for a rally event and throughout the days temp was in check, cruising at 210 and occasional 215 which then the auxiliary fan would kick on and the temp would go down. At the end of the day my t-stat out of nowhere fails open(fail safe t-stat) no spray under the hood, etc. I have a proper 16lb cap, proper fluid, etc...

Well I got it replaced under warranty because I had it for only 3 months. Swapped it out last tuesday for the new one and all is fine. Well this morning it's acting funny and taking FOREVER to get up to temp, which I assumed meant it failed open again, but when it does get up to around 195 and I start driving for a longer period of time, instead of the temp dropping straight down like its open, it went just below the notch near 210 like it could be stuck partially open?

I've never read of any partially stuck Tstats, only cases of either open or closed?

97' 4.0l

210 on the gauge is NORMAL operating temp, for the 4.0 motor. But yes a T-stat can fail and STICK in any position.

Yes, of course, a fail-safe t-stat usually fails on full open...once it has, it's toast. But any stat can fail in any position (not fully close or open). The wax plug & spring is not entirely rocket science. I used a fail-safe once, and it failed, did I say ONCE.

Using a quality OEM Dealer or Stant thermostat can lessen the possibility of failure. Always check the operation of a new stat in a pot of water, from cool to boiling to cool and see how it operates before installing it.

Some may ask of you have the stat in backwards, which was a possibility before 1990 or if you have an aftermarket t-stat housing. Barring that, the stat can only go in one way.