Remaining character count does not work

I’m using Ninja Forms 3.2.2, PHP 5.6.31 and WP 4.8.2. I need Single Line Text input fiels with character limits and custom masks. I was excited to see that Ninja Forms supports these input restrictions, but disappointed to find that the remaining character counts don’t work. Any key entry (even one that is ignored by the custom mask) causes the remaining character count to immediately go to 0 (zero). Deleting characters from the input does not increment the remaining character count. In short, remaining character counts don’t work.

Since I need the input restrictions but don’t want to display this bug, I have added the following style CSS:

/* Hide remaining character count until bug is fixed */
.nf-after-field {
  display: none !important;
}