Regression, Precise Calculator 2.6 when typing characters into the edit field only a single row of Pixels is drawn

0.4.12-RC-39-g27da885 gcc dbg is affected
Precise Calculator 2.6 from rapps

Observed result:
When you type characters [a-z] into the edit field, only one row of Pixels is drawn instead of the full character.
As soon as you type a number [0-9] then suddenly all the line is drawn correctly.
0.4.12-RC-39-g27da885_preciseCalculator_affected.webm
0.4.12-RC-39-g27da885_preciseCalculator_affected.log
During the typing nothing is logged, but eventually the log is still useful to see which fonts get used by the app.

Expected result
Whatever I type should be drawn properly and immediately.

I am pretty sure that this is a regression because
r73036PreciseCalc.webm (from CORE-12240) was still drawing the text properly.