The various sleep types don't add up to the total time. For example, the times from last night should equal 6:10 not 5:28. If it was just a few minutes, one could blame rounding but this is a 42 minute difference. (see pic)
How are you adding up to 6:10?
Look at the "Stages" tab. Perhaps there are some gaps in there?
Mkay, that makes sense. Those gaps occur when you watch is sitting either too loose or too tight (like when sleeping with your hand under your head) so the watch can't measure your HR correctly. You should see gaps in the HR graph as well during the night when this happens.
I don't think it is a Garmin Connect problem. Here are my sleep results for last night (everything adds up as it should):
HTH