Utopian bug when add contribution.

I don't know it is bug or not. But I think it is meanless.

Expected behavior

I entered 1105. at line head and I expected 1105. at line head.

Actual behavior

I entered 1105. at line head for my last translation and I realized this wasn't 1105. this was 1.
And I continued and typed 153156. this wasn't 153156. this was 2.

How to reproduce

I don't know, maybe it is a feature.

• Operating System:
  Windows 10

• Browser:
  Google Chrome 64.0.3282.119 (64 bit)
  Firefox 58.0.1 (64 bit)

Recording Of The Bug