MFP not communicating with Garmin CONNECT

Wait.
Almost always the answer.
Disconnect & Reconnect usually just extends issues because now there are orphaned sync packets between a specific connection that is no longer there that must be dealt with - almost always recommended against where there are issues.

Look at device at daily burn - subtract 500 mentally and note that number, look at MFP eating log, eat to that number.

ETA:
My Food diary total eaten just synced with Garmin, so that direction is fine for my account - so not some universal issue.
I haven't synced my device yet to Garmin to test the direction to MFP.

Just synced my device to computer and Garmin account - within 1 sec of computer saying done, updated my MFP Exercise diary and there's the adjustment.

So from Garmin Express to Garmin Connect to MFP account within 1 sec.

The function is not having an issue system wide.

Have you checked your MFP app settings for Step Source - it should say Garmin?

That setting tells MFP to accept sync packets from Garmin and use the data - otherwise it doesn't.

App updates or resets can cause that setting to default back to Nothing.

I just set up Garmin Connect to sync with MFP for the first time (newbie) and it cost me lots of frustration! I had to tell it to sync from both apps separately, and then re-start them. Might be worth trying.