Thank you @Valter-Santos, I found the errors in the log:
SYNC: Request ID 7392140811546959359 update devices failed: INVALID_ARGUMENT. Detail: Duplicated AgentDeviceId.DeviceId [baseVmFsdGVy-Q2hyb21l] in device [type: "action.devices.types.SWITCH"
Did you setup the SmartThings integration with TRIGGERcmd? If you have SmartThings linked with TRIGGERcmd and Google Assistant (Google Home), and then you tried to link Google Assistant with TRIGGERcmd, that might explain the duplicate device ID error.
I've never seen that issue, but I might not have tested that scenario yet. I will test it soon, and probably build a fix soon so you don't get an error.
But, if you have SmartThings linked with TRIGGERcmd and Google Assistant, you should have all of your triggers as SmartThings devices in Google Assistant. You would have gotten a duplicate of each trigger if the TRIGGERcmd to Google Assistant link would have worked, so I recommend unlinking SmartThings from Google Assistant if you want to link TRIGGERcmd to Google Assistant directly.