This was from the same batch of SS197SR with an '06 head stamp (this ammo came with the used PS90 I purchased).  This is two out of 115 rounds fired, but not all cases were recovered.
One casing I know came from my PS90, as that cartridge didn't cycle the action.
The other I found while picking up brass.  Looking at the cartridge shoulders, I'm guessing one was shot in the FiveseveN I rented from the range, due to one shoulder being noticeably more rounded... I read in another forum that the FiveseveN chamber doesn't support the cartridge shoulder and causes shoulder rounding like this.

Has anyone noticed split cases like this before from factory 5.7?

Also, I really liked the FiveseveN.  I'm going to have to get one now.

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These were (old) factory new loadings, supposedly loaded in p90 magazines for the last 10+ years.

I've also got 150 rounds of 198LF from around '06, which I'm slightly hesitant about now.

I've never seen split 5.7 case from factory FN/Fiocchi ammo

Happened again yesterday.

This was with my new Five-seveN MKII with about 400 rounds through it.

Ammo was a freshly opened box of SS197 head stamped '17.

I only managed to collect about a quarter of my brass, so I don't know if there were more.
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Splitting cases, with two different firearms,  with two different batches of ammo..........that's some bad luck there. If it were one gun then you'd send it and the ammo back to FN. With two separate guns I'm not even sure what to suggest outside of a serious inspection and cleaning of both and then try them out with a fresh box of new ammo. Good luck.