"Always Encrypted" in SQLServer2016 is not supported in SiteMinder r12.8SP5
SiteMinder r12.8 SP5 uses DataDirect 08.02.0187
"Always Encrypted" functionality is enabled from DataDirect 08.02.0244.
https://documentation.progress.com/output/DataDirect/odbcreadmes/sqlserverunixread.htm
SiteMinder r12.8SP5
We have the support plan in next release(r12.8SP6).