Wipe Tower for some filaments clumping/causing hot end collisions  

Wipe Tower for some filaments clumping/causing hot end collisions

Hi All. I feel I am moments away from finally getting a perfect MMU2S print...had a print going for past 12 hours then this morning I noticed a grinding noise as the hotend would wipe filament for the next filament pass on the tower...due to clumps of filament existing on the tower from the wipe. It doesn't look as though the filament is printing properly across the wipe tower...i.e. rather then it bridging across the tower its clumping together on the sides/insides of the tower (see the picture below). I decided to cancel the print as the hitting of the hotend on the tower was making me uncomfortable (and it would have probably failed anyway eventually).

I believe this is definitely an issue with the filament settings (Bilby3D PLA)...as the prusament filament passes on the tower run perfectly (i.e. the brown filament in the picture below) its only these cheaper filaments this is occuring. I've tried messing around with the settings of the filament like temperature...currently its set to 215c...any other settings i can try or missing? I have also tried drying the filament for a few hours as they were quite old.

Filament changing etc is all working great finally...just need this to be working then I should be good!