Yes, you may experience data loss. A real power loss protection would imply capacitors on the SSD. That's what enterprise-class ones should have, or an alternate mechanism just as viable.
Any SSD should to have some kind of protection against FTL (flash translation layer) corruption, or the entire SSD will be damaged resulting in total data loss.
Standard SSDs use a technique known as 'journaling' to prevent their FTL from becoming corrupted. This means that upon sudden power-loss, the SSD practically reverts to an earlier state, which comes in conflict with the flush cache command. In client computing (desktop, notebooks), there are 2 types of data defined: “data at rest” (data that has been physically saved to the storage media) and “data in flight” (pending writes - writes sent to the drive from the host computer but not yet committed to the storage media, or any write that is in progress, but is not yet complete, or in cache). In the case of power failure, the “data in flight” is gone.
In the enterprise-class SSDs, the capacitor circuits enable the SSDs to protect itself, to complete the pending / in-progress writes. The capacity is also enough to ensure that the FTL addressing table is properly saved to the NAND.
So, getting back to your case, in an unexpected power loss situation, the enterprise-class SSD will manage to write everything and have no losses while the other will likely have data losses. This will lead to RAID inconsistency.
What you should do is pair up the standard ones as an array and the enterprise-class ones as another. Keep the critical data on the protected ones and not that needed data (and pagefiles) on the standard ones.
