Same issue with Mivv slipon. Well it is not the slipon, but the pipe from slipon to Arrow pipe.
No problem with Akrapovic slipon which is supposed to work with OEM.
On the OEM threre is "gasket" (thick) on the pipe "stub" going from the huuge exhaust pot.
It seems like Mivv and M4 thinks it is a good idea to make a snug fit on the "stub" (not using the thick OEM gasket).
What I did was to buy a expander tool to make the Mivv "link pipe" fit on the Arrow "outlet":
2018 - Speed Triple S
2015 - GSX-S1000
2009 - B-King 1441