It is very easy to reproduce the mark issue. Basically it is only visible if the enemy casts; you cannot see the effect from yourself or allies. If an enemy champion hits you with mark (not a minion; only a champion as far as I am aware in 6+ games of ARAM), they recast to travel and then you see all sorts of disruption. Sometimes they travel and arrive invisibly briefly. Sometimes they do some weird teleport/model display backwards despite arriving to mark location before being clearly displayed after a delay.
In terms of the dashes, I am not 100% sure. I think it needs to be targeted and/or hit an enemy champion. Like I only noticed on stuff like lee, ww, quinn, maokai. Not so much on jarvan or shen. Also I think it is currently only a Howling Abyss issue but haven't tried normal with Quinn/Maokai yet. I hope this helps.