I am using STMCubeMX 5.2.0. That is the latest version. The issue persists. I just created a project for the Nucleo L476RG board. And there are the quotes again. Should I attached a screenshot?
I hope you do not expect to see syntax errors reported by GCC. Instead of being properly escaped, the quotes are stripped at some point and they are not passed to GCC. That of course is a bug in itself (!!!). Anyhow, for the CDT Indexer, the quotes are present, hence it cannot understand the syntax and it cannot properly index the files.
The CDT indexer is still being sabotaged - be it by STMCubeMX or by OpenSTM32. This is harmful to the usability of OpenSTM32.