I agree with everyone else here.
I assume you may have read the same online review of the Vibe + Dexcom that i did. The review i read made it seem like it was a huge issue with the Vibe, when in reality that reviewer just never posted the correct way to 'suspend' insulin.
If you are suspending insulin due to exercise you likely will never need to suspend completely, so you should more accurately do a temp basal to keep you from going low, but also to keep you from going high.
If you have a low and wish to suspend, just do a temp basal of -100% which effectively stops all basal insulin and will not suspend your dexcom.
Same goes if you want to go to the beach and take your pump off but keep your CGM on, just do a temp basal of -100% and you are good to go with the Dexcom still showing on the Vibe.