Swain's Nevermove counting as 2 abilities

If Swain successfully lands (E) Nevermove in combination with any other damage type (AA, passive pull, or ability) he is able to proc the runes Electrocute and Phase Rush. This seems to break the rules stated in the keystone descriptions requiring 3 separate abilities or attacks to activate them. Anivia's (Q) Flash Frost also has two instances of damage (pass through and stun detonate) but It is only counted as a single ability and requires more than just one additional type of damage to proc Electrocute or Phase Rush.

Is this a feature of Nevermove? Do other champions have abilities that are an exception to these rules or is this a bug?

This was originally brought to my attention by a SwainMains reddit discussion.