After Tahm uses his ult, the green circle indicating his ult is ready remains on despite him having just used it. The Tahm player cannot see the bug, as he cannot see his or her own green ult timer, but the other summoners can. This bug is intrusive because it causes a rift in communication. Summoners will often ask to take the Abyssal Voyage noting the green timer indicates it is ready; however, Tahm may still be on cool down from his last use.
This bug was active before patch 6.13 and is still active through today, patch 8.1. This is the forth time I have reported this bug.
To repeat this bug:
-Use Abyssal Voyage on Summoner's Rift with at least one other summoner
-Have another summoner note that the green ult timer still indicates Tahm's ult is ready before the cool down of Abyssal Voyage is over