I've also experienced this, although not having had the car long I'm unsure if it's an OEM filter. I guess it is as it was last serviced with you Joe.

I have fitted OEM filters for years without an issue.if yours are coming loose then your not tightening them up properly.simples.Fiat even supply the filter clamp to order.

They're being tightened to 14nm with a Fiat Hex filter socket but OEM work loose hence the thread.

No they don't work loose hence my reply.
14 nm doesn't apply to these.this is where the issue is
If you torque the filters then try them with a ratchet you'll still be able to move it half a turn.
As Crude as it sounds it has to be as tight as possible,the only thing you have to be careful of is that you check the oil filter housing bolt when removing the filters.

I've got to agree with JBT on this. I have never torqued an oil filter in the 20 years I've been servicing cars . I always tighten them up as tight as I can by bare hand and then give them a little nip more with some p40 sandpaper or something for a little more grip and I've never had a problem with a filter loosening off.

With my Coupé I've always used either Coopers or Fram oil filters (long and short length) and a cup wrench for slackening off and tightening them. I always check the thread in the housing to see if has slackened off (it's always been fine and never needed tightening) and when fitting the filter I always give it a good nip up with the ratchet and cup wrench,obviously nowhere near straining the threads of the filter but tight enough to satisfy me that it's not going to slacken off.

Baz

The report is tighten them
Properly and they won't leak.simples ..........