If you have no TDEV bound to the flash, pool, then there is no cause for concern and I would change or disable your alerting in Unisphere on the SSD pool.  In general, under FASTVP best practices, you want the SSD pool full with all devices bound to FC pool.  It's a good thing!
Guys - Checking if someone assist me on monitoring pool when we implement FAST VP on vmax 40k frames  well, i have three pools(SSD, FC & SATA) and i always map dev/lun to FC pool.... but i always get alarms that SSD pool is 98% used. at this moment im unsure on how to react if this values is normal. of course i understand that FAST-VP promotes and demotes LUN level data across storage tiers(EFD/FC/SATA tiers) to accomplish performance but I’m still checking below  SDD pool usage(94%) is still optimal.                         S Y M M E T R I X   P O O L S                        --------------------------------------------------------------------------- Pool         Flags Dev              Usable       Free       Used Full Comp Name         PTECSL Config           Tracks     Tracks Tracks  (%)  (%) ------------ ------ ------------ ---------- ---------- ---------- ---- ---- DEFAULT_POOL SSF-EI RAID-6(6+2)   909480720   185803141   723677579   79    0 123_tp_SATA_1    TSFDEI RAID-6(6+2)  1133247552 585256860   547990692   48    0 123_tp_FC_1        TFFDEI RAID-6(6+2)   743429220   418883160   324546060   43    0 123_tp_SSD_1      TEFDEI RAID-6(6+2)   214999260   2193864      212805396    98    0
FAST VP health check