Encoding ROT in messages 1,2,3

[mszablewski]

When encoding AIS messages using AisLib, (specifically for AIS Message 1,2,3). There's an inconsistency in ROT (Rate of Turn) value encoding and decoding. Despite setting ROT to a specific value (e.g., -4), the encoded message returns a different value (e.g., 1) after decoding.
Could you please confirm whether this inconsistency stems from a misuse of the library on my end, or is it an issue with the library?