QML TextEdit memory usage is extreme and the memory is not freed

When using simple QML TextEdit and pasting a lot of lines of text to it, memory consumption jumps by huge margin and this memory is never freed. When pasting text to the TextEdit and then removing that said text, the memory usage does drop maybe 10-20%, but rest of it is never freed.

It seems like the dimensions of the text have an effect on this; if you paste 200 lines of single "a" letter, and then go to the first line and add 1 "a" to that first line, almost 300kb of memory is allocated (for each new single added letter).

Reproduce steps:

• Run attached sample
• Observe memory usage
• Click the add 200 lines button
• Observe memory usage again
• Enter letters one by one to any line, observing the memory usage while doing it
  Expected:
• Memory usage stays somewhat steady as only one letter is being added
  Actual:
• 100-300kb of memory is allocated per letter