Cannot connect to Bluetooth keyboard: Unexpected continuation frame

I couldn't connect to my Bluetooth keyboard, with the following error message:

[  186.859882] Bluetooth: Unexpected continuation frame (len 11)
[  189.410011] Bluetooth: hci0: unexpected SMP command 0x0b from dc:56:10:d6:c4:06

I'm using Ubuntu on a laptop. My old WiFi adapter was MT7922, which didn't have good drivers for Linux and resulted in sometimes very slow inconsistent WiFi connections. Therefore, recently I switched to an AM210 adapter. Bluetooth worked in general. With the old MT7922 adapter, this keyboard could connect. With the AM210 adapter on Windows, the keyboard connects as well. I wonder if the 'Unexpected continuation frame' was because the keyboard thinks it is still talking to the old adapter. I tried resetting the keyboard, however it didn't work. Any clues? Thanks!