I’m assuming you mean the companion software rather than the ArduSub firmware (which is unrelated to the sonars), but glad to hear it
Still not sure what you mean by this. Are you just saying you need to click the device before it starts the profile display, or is there some other unexpected step you’re needing to do to get the connection to work?
That’s not expected behaviour, no. My guess would be your companion computer is either overheating or underpowered, or both. You can check the CPU status in the System page of the companion web interface - it will let you know if it’s low on voltage or throttling due to overheating.
Assuming you’re testing it in air, you may just need to let it vent and/or cool down for a while (the electronics enclosures are intended to be used in water - extended usage in air can cause the enclosed electronics to overheat).
On the power front, you may want to check your battery voltage. Separately, if you got your ROV before October 2018 then you might have our old 5V 3A power supply, in which case it’s likely a good idea to upgrade to our 5V 6A BEC.
If it’s none of those things then it could be a not great tether connection, but that’s unlikely if it was working fine before (Ping1D devices don’t require much data throughput).
There’s also the possibility that the lag is from your topside computer struggling to handle the video stream + mavlink telemetry + ping profiles. If you’re on Windows it may help to get QGC 4.1.4, which can force hardware decoding of the video stream. It’s perhaps worth noting the “Minimum Recommended Hardware” from the BlueROV2 Technical Details, which suggest at least an i5 processor, 8GB of RAM, and a solid-state drive.