The assumption that holiday episodes are non-canon may stem from the Mighty Morphin' Era and its questionable behavior with holiday episodes:

- Alpha's Magical Christmas: Green Ranger Tommy knows Adam, Aisha, and Rocky.

- Lord Zedd's Monster Heads: Season 2 had a Halloween Episode already before Rita's return. One could argue that its a Season 3 Episode BEFORE Season 3!

After Zeo, holiday episodes were on pause until they returned with Samurai, and the assumption is that they are non-canon in much the same vein.

Mighty Morphin' Holidays: Non-Canon and Mostly Forgettable (Best one forget that Alpha is a technical kidnapper)!

Zeo Holiday: Could go either way!

Samurai-Super Ninja Steel Holidays: No reason for them to not be canon!