Could be a problem related to your RTK base. What kind of setup do you have there?
If you have a F9P + RaspBerry Pi and U are also running the inject RTCM 1008 python script U should update it as there was two bugs in the code. It was discussed here on Injekt RTCM 1008 - #28 by esuomala
and eringerli has also got it fixed in his git: GitHub - eringerli/RpiNtripBase