I had not reported it because I wanted to verify if other people were having this issue before sending the developers off on a wild goose chase. Now that at least one other person has the issue, I can open one tonight. If it turns out that this is not really a dolphin issue, at least the BT passthrough wiki should be updated to indicate that even the Wii BT adapter is not perfect.
Windows 11 | i7-9700K | NVidia RTX 4060 Ti 8GB | 32GB DDR4-3000