DWM3000 invalid TX timestamp buffer reading

Hello, I am using the DWM3000 API and I noticed that when using the dwt_readtxtimestamp() function, the buffer that is being retrieved only contains 4 valid bytes, one of the bytes always being 0x01. Is this intentional? This affects my readings quite a lot, and so far I haven’t managed to fix it.

e.g (in base 10):
tx: 001 038 049 125 059
tx: 001 158 094 235 118
tx: 001 206 202 219 099

The RX timestamp buffer seems to be ok, as all 5 bytes are getting incremented correctly.