Installing two outdoor receptacles using T LB pvc, How many ground wires?
That conduit body is not large enough to contain a splice. You'll have to either run two grounds, or find a different place to splice.

References:


National Electrical Code 2017 314.16(C)(2); Allows splices, taps, and devices in conduit bodies, but only if the volume is stamped on it and it's large enough.
National Electrical Code 2017 314.16(B); Says that the CB would have to be at least 11.25 cu.in. to have a splice. (4 pass through conductors + grounds = 5 fill units. 5 * 2.25 = 11.25).


At least that's how I interpret the code.