Repeated 'Not a proper sync' messages

[ImmutablLimited]

Hi

I have installed this service and connected to my truma heater via a linbus > UART connection from my rpi3.

I am getting messages through which is great but they are consistently marked as 'not a proper sync' as per the below

Any thoughts?

in < ff ff not a proper sync -wait for sync- in < 80 5c not a proper sync -wait for sync- in < 84 21 not a proper sync -wait for sync- in < 80 7c not a proper sync -wait for sync- in < 80 dc not a proper sync -wait for sync- in < 11 a5 not a proper sync -wait for sync- in < 80 fc not a proper sync -wait for sync- in < a1 07 not a proper sync -wait for sync- in < 04 3f not a proper sync -wait for sync- in < 80 3c not a proper sync -wait for sync- in < e3 ff not a proper sync -wait for sync- in < 80 5c not a proper sync -wait for sync- in < fe ff not a proper sync -wait for sync- in < 80 7c not a proper sync -wait for sync- in < ff ff not a proper sync -wait for sync- in < 80 5c not a proper sync -wait for sync- in < e0 ff not a proper sync -wait for sync- in < 80 7c not a proper sync -wait for sync- in < f0 ff not a proper sync -wait for sync- in < 80 bc not a proper sync -wait for sync- in < ff ff not a proper sync -wait for sync-