is the presage and other 2 exotic rotators leaving anytime soon?

[undone condor]

If so should I use my harmonisers on some of the guns (got like 10 saved up)

[blissful wraith]

they are not leaving any time soo, but you should also use the harmonizers, as they are incredibly tedious to farm

[iron arch]

exotic mission rotator red borders are super rare. I run tons of tons of seraph mission but not a single drop of IKelos SG