Old PDF highlights unreadable after update to FW2.2.2

I just updated my Note to firmware 2.2.2 (from 1.8 I think) and found that old highlights now appear with a strange, impossible to read format. It looks like each letter is highlighted individually (see attached screenshot). Highlights format can be changed (e.g. to underline) but it still looks like each letter is highlighted individually. This format persists when the pdf is exported and opened on my PC. Highlighted text does still appear in the annotation list. Old highlighting in a MS Word document appears normal.

It seems that maxnd had a similar problem with a Nova pro with firmware 2.1.1
http://bbs.onyx-international.com/t/pdf-highlighting-height/1272

Is there any way to fix this highlighting?

Screenshot with new highlight above and old highlight below:

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