Loopback 4: HasManyThrough-Relation is not working

Bug or feature request

• Bug
• Feature request

Description of feature (or steps to reproduce if bug)

The HasManyThrough-Relation is not working properly.
Using the lb4 wizard I recreated the example

Link to sample repo to reproduce issue (if bug)

https://github.com/I3igI3uilder/example_sqlite_connector_bug/tree/main/src_not_working

Actual result (if bug)

• If you query for example with "http://localhost:3000/doctors/3/patients", it will give back all patients, not only the ones for doctor 3.
• If you e.g. try to include the patients in the doctors query, it will not result in an error, but it will also just ignore the inclusion.
• I have tested this with the memory connector and the postgres connector. Those two work properly.

Additional information (Node.js version, LoopBack version, etc)

Node Version: 14.15.1
OS: Windows

"@loopback/boot": "^4.0.1",
"@loopback/core": "^3.0.1",
"@loopback/repository": "^4.0.1",
"loopback-connector-sqlite3": "^3.0.0",

I would like to help fixing this, but this is beyound my reach.
Thank you for this great project.