Operating system: Windows 10 64 bit
Graphics card: GTX 1060 6 gigabyte (The old one)
Broken: Not sure this has ever worked, I tried two versions of 2.8 as well as 2.79 and they both behave oddly, example file is a 2.8 file though.
Short description of error
Toggling "even" on and off in the operator panel after doing a clamped edge slide changes the result, it seems to give you the results you would have had the edge slide not been clamped at all.
Exact steps for others to reproduce the error
In the example file, there are two vertices selected. Edge slide them in the negative Y (away from the main cube), press C to clamp, and then slide them in the positive Y so they're beyond where they started and confirm. In the operator panel, turn "even" on and back off.