[GAMEPLAY] Potential bug on Anivia

I have been noticing that Frostbite (Anivia's E) would not do doubled damage even though the target has been recently struck by Flash Frost (Anivia's Q). When I mentioned recent, I mean like 0.75 seconds after Flash Frost hits an enemy champion. Normally, Flash Frost would cause the target to be chilled for around two seconds, so even considering the enemy has additional tenacity, they should still be chilled after as short as 0.75 seconds. Now keep in mind that this only happens when the enemy have just got out of Glacial Storm (Anivia's R) and was struct by a Flash Frost.

However, I do understand the reason behind this potential bug.

Glacial Storm (Anivia's R) also applies chill to Anivia's enemies, but the duration of the chill debuff lasts much shorter than Flash Frost's aftereffect (it lasts roughly 0.5 seconds after the most recent tick of Glacial Storm). Now when an enemy was already chilled by Glacial Storm, they will not be chilled AGAIN by Flash Frost, which means that the duration of the debuff only accounts for 0.5 seconds (Glacial Storm) instead of the new 2 seconds (Flash Frost).

I am a Challenger that has been playing Anivia for many seasons now, and I do not believe that this problem has occurred in the past. Now I do not know if Anivia's abilities were intended to work like this, but I believe a potential bug fix (if this WAS a bug) would be to prioritize the chill debuff duration on Flash Frost if an enemy was hit by BOTH Glacial Storm and Flash Frost.

Please let me know if this has happened to any of you fellow Anivia players!