Highlight does not seem to work correctly

[ghost]

I am currently using coc.nvim with the coc-clangd extenstion.
I hardly have any highlighting and the log output is:

Di 02 Mär 2021 19:01:49: stopped hl_symbols timer
Di 02 Mär 2021 19:01:49: hl_symbols (textprop nvim) highlighted 2 symbols in file Source/ToonTanks/Pawns/PawnTank.cpp
Di 02 Mär 2021 19:01:49: operation hl_symbols (textprop nvim) Source/ToonTanks/Pawns/PawnTank.cpp took   0.000303s to complete
Di 02 Mär 2021 19:01:49: operation hl_skipped (textprop nvim) Source/ToonTanks/Pawns/PawnTank.cpp took   0.000024s to complete

And only 2 highlighted symbols seems very odd to me for a code of 75 lines of c++.

I also tried using ccls to make sure it has nothing to do with me using clangd, as support was quite recent as i understood, but there still isn't any more highlighting.

Have I done something wrong? ( I have set the relevant settings in the coc-settings.json
Any help to get this working would be greatly appreciated!