I am using aerender.exe to run multiple renders on the same project. When I set the increment (-i option) to a value greater 1 (let's say 2), aerender correctly skips ever other frame. It renders frames 1, 3, 5, 7... and so on.
But it stores those frames in files with sequence numbers 1, 2, 3, 4, ... (not 1,3,5,7 as expected).
This seems to be a bug, and it causes a serious problem if two or more renderers work on the same project: When one of these renderers checks if frame 3 has already been created, it apparently uses the actual frame number (3) to construct the file name. But frame 3 is stored in file number 2. So it assumes incorrectly that it needs to create frame no 3. It's a mess!
Is Adobe aware of this problem? Is there a solution or workaround of some sort?
Sounds normal. It's just a dumb render override, after all. I've never used network rendering much and least of all this option, but according to the help it says nothing about honoring the source time. Could and should it be changed? Probably, but for the time being you may have better luck defining these things in a custom render setting you call up in your command line renders. Or to put it another way: You are probably using the setting in a way it was never intended and that's causing trouble.
A few years ago I also rendered using aerender directly over the network. Don't set the increment option this way - but rather check the "skip existing frames" option in the render settings inside AE render queue.
This way, all renders will start at frame 1, but will skip this frame, if another renderer is already on it. No issue with file names.
This is not the best approach in general. When rendering times of each frame are very low and you are running a lot renders and let's say, 40 frames rushing to the shared drive at once, it can happen that two renders try to render the same frame. In this case, one render is killed due the acces rights violation.
A better and more bullet prove approch is to give each renderer it's own frame span. Unfortunaltly AE cannot do this for you automatically.
If you are using network rendering often, or want to improve rendering times in general, I recommend RenderGarden. This is a little manager which does exactly what I just wrote. Next to RG, there are also RenderBoss (more remote control) and BGRenderer (cheaper).