You cannot assume that. There are a many reasons to flush a TLB entry, such as:
- The TLB is full, and a new entry needs to be cached, and the entry in question is replaced with the new one.
- There is an instruction to explicitly invalidate a TLB entry, which can be used for such pages as well.
- There are many other conditions in which HW will flush the TLB completely in order to maintain consistency for reasons other than CR3.
In short, you cannot assume that once a page translation is in the TLB, it will always remain there.