Serial Flash Controller II - erase / program issue

On a customer board (Quartus Prime 18.1 / Cyclone 10 LP / W25Q64) I use the Serial Flash Controller II to access the serial flash W25Q64.

Programming of the flash with JIC-file/Quartus-programmer and booting works fine. However, programming serial flash with Serial Flash Controller II / NIOS does not work reliable. The controller is accessed via the API in the source-file altera_epcq_controller2.c.

Sine it does not work reliably, I monitored the signals to the serial flash. I noticed that after erase or programming actions the busy signal of the flash was not evaluated.

For this purpose I found the function alt_epcq_pll_for_write_in_progress in source file altera_epcq_controller2.c. So I implemented this function in erase_block and write_block (altera_epcq_controller2.c).

After this change erase and programming works reliably.

Is this a known issue and is there a patch available?