I have worked out a work around that I think has been mentioned before
1) The % split of the TT- T3 Box 21 of the T3 summary does not carry into the individual spouses Total Capital Gains Schedule 3 Line 17599 and 17600.
2) When you add the amounts into the Box 52 and Box 53 of the TT- T3 summary the amount will not pick up the % split and applies 100%. That is why it appeared to double up as it was not picking up Box 21 at all in the first attempt.
3) If you split all the amounts from the T3 and thus submit two T3's one for each spouse it will work and the error appears to be cleared. NOTE: Box 21 must equal Box 52 plus Box 53. and those boxes populate CG schedule 3 Line 17599 and 17600.
I hope this helps
