Playback through Xfinity streaming web site while recording won't fast forward or rewind

I am experiencing an Xfinity Stream playback issue on my Windows PC using Microsoft Edge at xfinity.com/stream. When I watch a DVR recording that is still in progress, pressing fast-forward or rewind, or moving the playback slider, sends the recording back to the beginning. Completed recordings work normally, and the same in-progress recordings work correctly on my iPad. This appears to be an issue with the web player. Please confirm whether there is an active engineering investigation and whether a fix is available.

Thank you