After encryption, BackupAsync throws an exception

[tzengshinfu]

Environment
.NET Framework 4.8.1

Packages
sqlite-net-sqlcipher 1.9.172

sqlite-net-pcl 1.9.172
SQLitePCLRaw.bundle_green 2.1.2
SQLitePCLRaw.core 2.1.2
SQLitePCLRaw.lib.e_sqlite3 2.1.2
SQLitePCLRaw.provider.dynamic_cdecl 2.1.2

Scenario
After encryption, InsertAsync, UpdateAsync, and DeleteAsync all work normally.
Only BackupAsync throws an exception with the following message:
System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.