Parallel of transformers. Is R/X condition necessary?
Looking at the equivalent circuit as being constructed from ideal components, it is not necessary for X/R to be equal. In addition/ X/R can only be equal if R1 = R2 and X1 = X2. Considering factors such as temperature coefficient of resistance, the transformers will not share the current equally unless they are identical in every way.

Consider that the drop across the parallel combination of R1 + jX1 and R2 + jX2 is V1. The current I1 = V1/Z1@a and I2 = V1/Z2@b where a and b are phase angles determine by X/R. If Z1 an Z2 have equal values but different phase angles, the currents I1 and I2 will also have equal values but different phase angles.