I have found errors in the latest version V 2 of the plug in, Arturia are aware and Kevin has apparently solved it but it has yet to be released.
In your pro tools plug in folders, both Avid and Digidesign, delete Spark.dpm & Spark.aax
/Library/Application Support/Avid/Audio/Plug-Ins/Arturia
/Library/Application Support/Digidesign/Plug-Ins
Once these are deleted, please install the below version of the Spark.aax plug in
https://www.dropbox.com/sh/jhlmzb1bfoh1hz5/AAAKw-CQCtosgJ6c8btBbTdTa?dl=0Drop the above plug in, into /Library/Application Support/Avid/Audio/Plug-Ins/Arturia
Restart all and see where you are.
Out of interest, what sample rates are you using, 192k?
Spark will probably only play back up to about 88.2k, possibly 96k. I did test this a while back and found that all my 192 sessions would not play.
It works fine at 44.1k, not ideal but what I tend to do is print the audio from Spark in a 44.1 session, Apply SRC and save session as copy in 192k. Then start tracking the rest of your session
I'll send you over a working session, it will also have audio tracks to print to, you may have to re-assign your I/O. Also when using multiple outs in spark, I start at 2, don't use master on the first track. Again, a pain up the do dar but rarely you will need 16 drums I imagine so start at 2 and go to 15. I've chatted to Kevin at length about this, ideally master should be different to 1-2 but there is some reason why they cannot split the outputs.
Downloading that older plug in should sort out the issues and deleting the old dpm plug will also go to helping the issues.
Hope that helps,
Stuart