I'm having a similar issue.

Sometimes when my system has been idle and the monitor has turned off the main windows taskbar on the primary monitor almost disappears. You can just see the top edge of it but cannot use it. Killing and restarting explorer.exe fixes the problem. The main monitor is a Samsung 4k TV that turns off when it's been idle for an extended period without an image.

I'm using the multi-monitor taskbars but they are unaffected, only the main windows one is affected.

My system is running Windows 7 and has an NVIDIA GTX960 with the very latest drivers. I just updated to 359.06 today but been using the PC all day so not sure if there is any change in the problem I'm seeing.

I attached the information you requested.

I also noticed the logging options so I temporarily turned on logging whilst I re-created the problem. I did two runs one with detailed and then again with minimal.

Steps for me to re-create are:
1) Start Display fusion logging
2) Allow PC to go into screen save
3) Power cycle the primary monitor (it powers itself down after extended away time)
4) Move the mouse to wake up the PC
5) Main task bar is unusable, you can just see the topmost edge. Display Fusion task bars appear normally.
6) Stop Display Fusion logging
7) Kill explorer.exe and execute a new explorer.exe to fix the task bar.

Well interestingly enough it's stopped doing it.

The only thing I can think of is I enabled auto-hide on the taskbar. But now with or without auto-hide it works fine.

Of note is that when it was misbehaving it looked the same as an auto-hidden taskbar with just the "edge" showing. Wondering if setting auto-hide and then un-setting it made it work.

I spoke too soon, it's misbehaving again.

As you suggested I tried exiting Display Fusion before the monitor enters sleep and it all comes back on without issues (tried that a few times). Also of course it only malfunctions when multi-monitor taskbar is enabled.

I have the primary monitor split into three and one of the Display Fusion taskbars was set to autohide "Enabled, Shown with Windows Taskbar".

I tried various combinations of the taskbar settings, including it to just enabled and not using auto hide at all and I seem to be able to reproduce the problem in all cases.

The only configurations that seem to be free of problems is not using multi-monitor taskbars at all.

I believe I have found a configuration that avoids the problem. I moved my primary taskbar (Primary display) to a monitor that has no splits. Then using multi-monitor taskbar to display taskbars on the large split monitor.

Have not managed to re-create the issue yet

Yes I have not seen any issues with the Displayfusion taskbars disabled whilst the monitor sleeps. I can re-enable them after and they work fine.

I am already running the Beta version, however I have upgraded to Windows 10 since I reported this issue, so I'm using the native windows multi-taskbar. So sorry I can't test the Beta version to see if I can re-create.