DHCPv6Bind fails using STC API for STC Version 4.87

When running DHCPv6Bind in my tcl script I get the error:

DHCPv6: Bind Sessions 1Invalid handle in Connect command hnd(3246), expected port handle(s)

I run the command like this:

stc::perform Dhcpv6Bind -BlockList "dhcpv6serverconfig1 dhcpv6blockconfig1"

The "stc::get dhcpv6serverconfig1 -ServerState" returns the state of Server is up

The "dhcpv6blockconfig1" is a result of stc::config dhcpv6blockconfig1 -UsesIf-targets " ipv6if47 "

Any idea what is the issue here?

As same script was running for STC 4.73.. Maybe sth changed in 4.87 version?