The pass4SymmKey is encrypted using splunk.secret, so you're likely copying an encrypted pass4SymmKey to hosts with different splunk.secret files.
Do you know what the plain text pass4SymmKey was set to on the License Master (LM)? If not, you can just set a new pass4SymmKey on the LM in plain text, restart it, (it'll encrypt automatically after restart), and use the same plain text pass4SymmKey/restart process on the other LM slaves.
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