Currently, the 'Envelop' effect is not supported with Symbols in CorelDRAW.
This feature could help e.g., when you are creating garment designs and you need to present the designs to clients just like a real garment wrapping around a figure.
Repetitive elements such as logos can be used most effectively when creating a symbol from it, any copy instances while the symbol master can be changed to apply the changes to all instances. However, in order to present these elements as wrapped you need to be able to use the 'Envelop' tool with symbols.
Right now, the symbol needs to be reverted to its original objects which results in the symbol functionality being lost. When applying the 'Envelop' effect to a symbol the element will maintain its symbol functionality, the symbol master can be updated and the "enveloped" instances will be updated with it.