If you have another shared datastore visible to the target cluster, you could add that as a second placeholder datastore and test.

Otherwise - you mentioned in your initial post that you re-installed already. Did you create a fresh database when you did this, or did you retain the previous data?

If you used existing data, have you already tried just removing the placeholder datastore, then selecting it again (via Sites > Manage > Placeholder Datastores)?

If you are in a situation where you have to use the same datastore for your replica VMs and your placeholders, and removing/re-adding the placeholder datastore hasn't worked, I can't think of any other options. Probably best to open a support request so that it can be looked into in more detail.