Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F415xx_v2/IOMUX/REMAP8#0x0
IO MUX remap register 8
TMR1 BK1 CMP muxing
TMR1 CH1 CMP muxing
TMR2 CH4 CMP muxing
TMR3 CH1 CMP muxing
https://github.com/cmsis-svd/cmsis-svd-data