For the users with the sources, the problem is in procedure OracleData.SetFieldSize. I guess it uses wrong offset somehow, so TField's FDataType is overwritten instead of FSize.

For ones without the source code access, you can patch the OracleData.dcu manually:
32bit - address on 2E0708 needs to be 58 instead of 50
64bit - unfortunatelly offset is too large for this instruction to be fixed, it needs to be replaced which breaks the dcu and I have no idea about dcu format. Thankfully it is working fine without fixing anyway. However I was not feeling comfortable knowing that some fields are just ramdomly set, so I have changed the three-byte instruction to three one-byte returns (addresses 4A2703, 4A2704, 4A2705 to C3)

Hopefully we get the official fix soon.