Charger blinks red at the end of charging, not charging

Hi, my Samsung Gear Sport SM-R600 recently started having charging issues. The factory charging dock will start blinking red at the end of a charge and my watch will begin draining its battery. I typically place my watch in the dock every night (power is usually at around 50%) and have been recently waking up to less than 15% charge in the morning, which is strange because not charging the watch would have left me with more power than putting it on the dock (a full charge usually lasts me roughly 2 days).

I have tried the following:

• Different outlet
• Different USB charger (same dock)
• Different USB cable
• Deep cleaned watch back and charging dock face
• Rebooted

None of these have shown any improvement. Also, I have yet to do a factory reset.

Any idea what the problem might be? I am thinking of purchasing another charging dock to see if that is the issue, or perhaps there is an issue with my watch battery? Other than the charging issue, my watch performs just fine. The battery life is just as good as before.

Any tips, tricks, or recommendations would be greatly appreciated. Thank you!