Arc not compatible with spell echo

Hey my spell echo stopped working 2 nights ago. It was fine Right after the update but now it's just a waste of a gem. The tooltip says it's increasing my cast speed but it isn't. Or casting twice actually.. Here's a short 17 second video and i hope you guys check this out. I don't have a lot of time to play so it's kind of frustrating that my build can hardly handle teir 7 maps because of this. My arc is level 19 and spell echo level 17. I hope this gets resolved soon:) i tried spell echo with storm brand and it works just fine. It only seems to be my arc ability that it's ignoring. Thanks guys! https://youtu.be/Z73TNBSZnoE

you're casting a different unsupported arc gem. Look at the ability icon in the bottom right, no supports. Did you change your weapon set recently? You have the wrong arc equipped.

Edit:
To further explain, if you have multiple ability gems of the same type (multiple arc gems) which is common for leveling additional gems to vaal it's possible to hotkey the "wrong" gem. So your button is bound to the solo arc gem you're leveling not the one in the 5 link.

This can commonly occur if you swap your weapon set, as you can have different skill bindings for different weapon sets. If you never set the second weapon/skill set, it will default looking for an ability starting in the top left of your gear, moving to the bottom right. It just "happened" to find the leveling arc gem, and put it in the same binding as your main arc gem normally is. This happens a fair amount.