WWE issued the following statement regarding streaming issues during the Fastlane pay-per-view:
"Any issues occurring with tonight’s broadcast of #WWEFastlane will be addressed in the future."
Aside from the stream being behind 45 seconds or so on Peacock, we have not heard of any significant issues on the WWE side of things or on Peacock.
The reason why WWE and Peacock are simulcasting the event on both services is to work out any issues ahead of WrestleMania 37 in a few weeks. If you are experiencing issues watching the show on Peacock, WWE says those issues will be resolved soon.