In that match, Real Madrid did not field the main squad and the back row was also filled by two defenders who did not have sufficient flying hours. However, regardless of the many goals conceded by Madrid lately, it was indeed because the crisis in the back line was very severe. Of course, the victory was an important capital and became motivation for the team to return to the path of victory.
Only a few people were not fielded as starters by Ancelloti, but can that be a justification for the weakness of Real Madrid's playing pattern. Moreover, the players who benefited from Ancelloti were much better than the Leganes players themselves and Real Madrid should not have had so much difficulty. Although the back line crisis is indeed being experienced by Real Madrid due to injury factors, Ancelloti should have understood the need for victory in every match much better and was lucky enough in that match that Real Madrid managed to win the match.
That is indeed a problem for Real Madrid this season, even if they field the entire main squad, the performance of the lower line and the Real Madrid midfield is still in the spotlight because it is inconsistent in its performance, especially when Ancelotti makes a lot of rotations like in the match against Leganes.
Even though Real Madrid won, Real Madrid's performance was quite bad and I didn't even highlight the defense line alone, but Real Madrid's game was not well organized in all lines so they had difficulty against a team that actually had much weaker strength than them.