It seems that code point 0x2308 (LEFT CEILING) has been changed from the "Sm" category to the "Ps" category starting from Unicode 6.3.0. This means it no longer matches the \w escape, causing the instance test to not validate.
There may be other characters that are affected, this was the first one I found, and seems to be the only test that fails on Unicode 12.1.0 due to category changes (block changes are another thing, but that is addressed in the spec).
Also the same for code point 0x2309 (RIGHT CEILING), changed from the "Sm" category to the "Pe" category. The other codes are right according to Unicode 12.1.0.
It seems that code point 0x2308 (LEFT CEILING) has been changed from the "Sm" category to the "Ps" category starting from Unicode 6.3.0. This means it no longer matches the
\w
escape, causing the instance test to not validate. There may be other characters that are affected, this was the first one I found, and seems to be the only test that fails on Unicode 12.1.0 due to category changes (block changes are another thing, but that is addressed in the spec).