Reduced contrast on bolded words on Kindle

[SpeedyReader]

Since the recent Kindle updates, the Fast Serif and Fast Sans font has low contrast on the bold portion of the word in comparison to the regular part. Is there a work around for this? Unfortunately, I am not savvy enough to rewrite the fix. The contrast is even less in the fast serif ttf.

Thank you for your time, this font is really helping my students process their reading faster and with more cognitive retention.

[Born2Root]

Thank you for reporting the issue!
I was not aware that they have changed something on the Kindle.
Since I do not own a Kindle, I am not able to reproduce the issue.

Can you tell me if the lower contrast applies on all bold words, also with other fonts?
Or is it only affecting the Fast-Fonts?