Numbers - problems with a formula for "text to columns" behavior
Can you try these pls (assuming the text to be separated is in B2)?

C2 = LEFT(B2,FIND(",",B2)−1)
D2 = MID(B2,FIND(",",B2)+1,FIND(",",B2,FIND(",",B2,)+1)−FIND(",",B2)−1)
E2 = RIGHT(B2,LEN(B2)−FIND(",",B2,FIND(",",B2,)+1))


They should work for all values of non-zero length between the commas assuming there are always exactly 2 commas.