I noticed this a couple days ago. I was busy working on something with a time crunch, so I just changed the Space Units / Units in workspace / Format to Decimal and continued.
To get a Fractional display in the Inspector Bar, adjust Precision (just above Format) to have just enough information for the Inspector Bar to choose the correct denominator, but I must have been doing that wrong and was just too hurried to figure it out.
TC Pro Platinum 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