I experienced the same problem as stated here Interrupt stops triggering on DWM1001
The problem is if you plan a transmission with a delay that is really close to the minimum delay needed by the chip to prepare the transmission. The chip doesn’t set the error flag and never return the interrupt fro transmission completed.
Forcing during init the TX clock helped me limit this issue, this is done in PMSC register : dwt_write8bitoffsetreg(PMSC_ID,PMSC_CTRL0_OFFSET,0x20)
What I’d like to know are the implications of enabling the tx clock per default to get rid of this issue. I did not find anything in the dw1000 user manual.