The next time you use the Offset command, check the Inspector Bar. I have noticed, sometimes, that the function starts up with a value in the Offset that is locked (a locked padlock is displayed immediately above the entry gadget) . If so, you will want to unlock and try from there.
TC Pro Platinum 2019, 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1