Scrum discourages proper design and/or consistency in the code by focusing on getting the work done as fast as possible, not on doing it properly.
The tax you are paying for using Scrum
Martin Griggs

Unfortunately, it’s a false statement. Agile & Scrum — they both support proper design and well maintained code. The truth is that quite often companies does not follow some principles. Personally I think it’s a problem with implementation & understanding.