Error reading S7-1500 DB through Kepware OPC

From a S7-1500 I have to read the bits of the last two bytes of a DB (bytes 3848, 3849). Ignition cannot read those bits: tag quality is Unknown. Going to the kepware log I see the following reading error:

It seems that Ignition is telling Kepware to read 3 bytes from 3848: is there any reason for that?
My bits are defined by using a UDT as follows (StartByte=3848):

Any suggestion?

Thank you in advance


Is it possible that any of the other tags in your UDT are addressing past 3908?

Thank you Kevin. I’m quite sure that’s not the case: I double checked the tag database definition and all my variables are within DB addressable range - anyway I will check it again.