I found a bug where MongoDB running on a Chinese Windows 10 system encounters an error when executing rs.status() in a replica set. My replica set consists of three MongoDB instances. When all three instances are running normally, rs.status() returns the correct result. However, if one MongoDB instance stops running, rs.status() only returns BSONError: Invalid UTF-8 string in BSON document. The reason is that the software reports an error due to not receiving the heartbeat packet from that instance, and the error message contains strings from the Chinese Windows 10 system. These strings are not in UTF-8 encoding, causing rs.status() to fail.

A temporary workaround I found is to change the language for non-Unicode programs in Chinese Windows 10 to English, which temporarily resolves the issue. However, I hope MongoDB can fix this bug.