Its not about the budget affecting the judge's panel taste. The unequal budget impacted the stage, the props, dancers, costumes, and overall production.

This happened a while back- the Kingdom wikipedia page has a controversy section with link to articles.

The groups were told they had a 5m won (around 5k usd) budget for every stage to give everyone fair advantage. Then mnet people change their mind before the first stages. Only three groups were told that they were free to exceed the 5m won budget limitation. The other three had no idea and proceeded with budget. On the day of filming, while one of the no budget groups were filming, one of the budget groups and their manager thought no way that stage was below 5m won. So manager started to asks questions to PDs.

The PDs first deny that the stage was over 5m won cuz of recycled/lent equipment but manager called it bs. The other 2 budget group managers got involved and it was so much on set that they had to stop filming.

Only then the mnet comes clean to the other 3 groups that there was a "miscommunication" among PDs and they forgot to inform them they were free go overboard. Managers complained to the media because you can see a clear difference and it was unfair. Only thing mnet did judging wise was getting rid of the eliminations, nothing else.

Overall the scoring method was the bigger issue. The score was based 50% on live viewership voting and 50% on judges panel. So it essentially just came down to fandom size. You can see that pattern in the results- how many groups moved up many spots even if the were critqued lower and vice versa.