Nothing is broke, so a fix isn't needed on WGT's end.
The problem is at the player's end.
WGT is effectively the tournament committee, and can set the Conditions of the Competition as provided for in the Rules of Golf - Appendix 1, Part C.
Many WGT players equate WGT golf with casual amateur golf where there is no tournament committee.
WGT doesn't calculate a players handicap and instead uses the professional golf model of a Stroke Average. In other words, WGT is set up according to most of the common tournament play Conditions of the Competition.
One of those conditions is known as the One Ball Condition that requires a round be played with the same make and model of golf ball. In the RoG a breach of the One Ball Condition causes a penalty or disqualification.
WGT imposes no score or disqualification sanctions, and instead gives the player a free, you-can't-lose-it-or-wear-it-out ball to finish the current game with.
WGT warns players when they start using their last ball, and gives the player an immediate opportunity to get another sleeve of the ball in play so the player then has 4 legal balls
If the player manages to lose 3 of the 4 balls in the course of the game WGT will again inform the player when they start using their last ball, and gives the player an immediate opportunity to get another sleeve of the ball in play so the player then has 4 legal balls.
Players who ignore WGT's notifications put themselves in the 'finish the round with the Starter ball' situation.