Cell size at division is determined by the balance between cell growth (the increase in mass or volume) and the timing of cell division.‬‏ Decreasing growth rate without a compensatory reduction in proliferation rates will decrease cell size . The converse is also true: increasing growth rate in lieu of increased cell division rates will produce large cells.

I think that the stimulants of cell division in the food medium that you use a high percentage. Therefore, this may be what accelerates cell division before it reaches its assumed size

Try to change the proportion of materials in the medium and see what will be produced.

https://www.frontiersin.org/articles/10.3389/fcell.2017.00115/full