In Firefox, PlatformUI validation causes the following error(in at least integer and float):

Unable to check <input pattern='\-?\d*'> because the pattern is not a valid regexp: invalid identity escape in regular expression

This results in being possible to publish contents with invalid field values, however the field is set to empty.

The cause seems to be related to Firefox change in the HTML input pattern. see https://www.fxsitecompat.com/en-CA/docs/2016/input-pattern-now-sets-u-flag-for-regular-expressions/