I have the same problem, but it only happens with the first rig listed in EthMan,  rig_0. The other two miners listed below it in the same EthMan instance are reporting fine. The timeout for the first rig was also present on v10.2 with the Crimson Relive 17.11.4 drivers. It makes no difference if EthMan is running on that rig or another rig. It seems the connection is dropped intermittently on the first rig. I noticed in the Opitions.ini, the [rig_0] password will remove the quotation marks before and after the password, even if I put them back. I don't know if it's related to that since I also tried running it without a password and the same thing happens. All the rigs are running the same v3.7 of EthMan.