Loses heart rate during the day

I frequently have this issue but for me only at night ! There are gaps in my heart rate and sleep data both on my watch and the Connect app. Never happens during the day for me

I get the same gaps in pulse data and sleep data. Got one 245 replaced for that issue but it’s happening with the new one as well. Very frustrating that it’s happening with a completely new product. 

My watch is a replacement too but still keeps happening. I'm just hoping the next firmware will fix it

If you're getting gaps only during your sleep and it's happening again with a second device, it seems pretty clear the device is OK and the problem is it's moving on your wrist while sleeping. Either it's too loose and shifting, or the watch is under your head or body and applying to much pressure. If it was happening throughout the day, then it could be something to be concerned about.  The watch doesn't know when you're asleep. It will look for a lowered HR, and setting your sleep time in Connect will assist.  You can easily verify this. Temporarily change your sleep times to something outside your normal sleep window. I'm certain you'll still have the same issue while you're actually asleep even though the watch is outside the set sleep period. 

For me it has happened during the day and the night but most often during the night. Ive had gaps in the middle of being out walking, or immediately after waking up and it’s registered steps but not pulse. It’s just odd. 

It's tracking steps because your accelerometer is working properly. Your HR gaps are an issue with the oHRM sensor. When you notice it stops recording, is the green light still on?  If not, contact support because it should be on.  If body hair or complexion was the problem, I think it would be constant. This leaves fit as the most probable culprit. If too loose, movement or light will cause problems. Are you certain this isn't the case? If you are certain this isn't the problem I would contact support because the device may be faulty. There are very few posting about this and if fit isn't the cause, I doubt a fix with a FW update is even in the making.