成唯識論演祕 2.493

2.493

等言等彼有覆、無覆，長途所起名為恒行，非不間斷名恒行也。或疏脫也，應云不恒行。

The word 'and other' equates to the defiled and undefiled [neutral]; that which arises over a long course is called 'constantly functioning', not that it is called constantly functioning because it is uninterrupted. Alternatively, it is a textual omission in the Commentary; it should read 'not constantly functioning'.