Upgrading MemoryPack to new version breaks Serialization

Post upgrading from 1.21.1 to 1.21.4 . Getting the following exception on DeSerialization of an existing binary which was Serialized with 1.21.1

" MemoryPackSerializationException: {CustomData} is not registered in this provider. "

This "CustomData" is already marked as [MemoryPackable(GenerateType.VersionTolerant)]. 

PS: Reverting back to 1.21.1 works fine.