ID:176182 Bidirectional pin <name> with pseudo-differential I/O standard has the input buffer driving fan-outs. For such cases, the assignment "Allow Single-ended Buffer for Differential-XSTL Input" (XSTL_INPUT_ALLOW_SE_BUFFER) should be used instead of "Treat Bidirectional Pin as Output Pin" (TREAT_BIDIR_AS_OUTPUT).

CAUSE: You used a bidirectional pin with pseudo-differential I/O standard and fan-out on the input path with the TREAT_BIDIR_AS_OUTPUT assignment. However, if you want to use such a configuration, use the XSTL_INPUT_ALLOW_SE_BUFFER assignment instead of the TREAT_BIDIR_AS_OUTPUT assignment.

ACTION: Replace the TREAT_BIDIR_AS_OUTPUT assignment with the XSTL_INPUT_ALLOW_SE_BUFFER assignment.