Cyclomyces (type C.fuscus ) and Hymenochaete (type H. rubiginosa) do seem to be congeneric and the shift accepted in the recent literature.
https://doi.org/10.1007/s11557-006-0008-9
http://doi.org/10.29203/ka.2017.483.

The older name Cyclomyces was recently rejected in favour of Hymenochaete.

Cyclomyces tabacinus = Polyporus tabacinus (type Juan Fernandez islands, 1835)
= Hymenochaete porioides (a replacement name in Hymenochaete).

However Ryvarden (1981) established Polyporus microcyclus (type Java, 1844) as a synonym of Cyclomyces tabacinus in a bare-bones statement and no systematic revision. So, under Shenzen 11.4 it must be used as the basis of the correct name, which becomes Hymenochaete microcycla. Probably it is quite reasonable to call the Asian/Austrasian taxon H. microcycla. It could be the South American C. tabacinus turns out to be a different taxon when the molecular work is done.

No doubt there are other earlier epithets waiting in the buried archives to overturn this again, for example Quentin's odd 1997 treatment “Opera Botanica Belgica 11, Volume 11, THE POLYPORES (POLYPORACEAE S.L.) OF PAPUA NEW GUINEA A PRELIMINARY CONSPECTUS” has Polyporus spadiceus Jungh., 1838 as a synonym of C. tabacinus and should take priority ... at the moment. But let's be sensible and ignore that.