After contact with microsoft helpdesk I found the solution for me.
For future reference: I had to turn on mss clamping and set it to 1350. This is also in the advanced IPSec settings
Maybe this settings was defaulted after an update? I wasn't the one who configured it in the first place, so I wouldn't know for sure.
I made sure to match my settings to this document https://docs.microsoft.com/nl-nl/azure/vpn-gateway/vpn-gateway-about-vpn-devices
@stephenw10 Thanks for the reply, I had this disabled already, but the pointer was appreciated