Clustered environment is not supported by lvmetad yet. If global/use_lvmetad=1 is used together with global/locking_type=3 configuration setting (clustered locking), the use_lvmetad setting is automatically overriden to 0 and lvmetad is not used in this case at all. Also, the following warning message is displayed:
WARNING: configuration setting use_lvmetad overriden to 0 due to locking_type 3. Clustered environment not supported by lvmetad yet.