This problem was caused by updating the Administrator component of RSForms! Pro in latest iteration (3.4.2). In a Checkbox Group, the Caption entered during construction of the form is displayed normally as a title to the left of the checkbox, but it is now also displayed in a different color and font size to the right of that, above the checkbox, pushing the checkbox down well below alignment with the title. In the source code it is labeled as <legend class="rsfp-visually-hidden"> but it is not hidden. The location of the code is not accessible either in XAMPP or on a live server (inaccessible folder under /media/com_rsform/css/scss/_reboot.scss, although hidden items are displayed). The only way I could remove this "legend" was to go into each form's Form Properties and select the CSS and Javascript area. At the bottom of the <style> area in the first text box, I entered:

.rsfp-visually-hidden {
display: none !important;
}

I tried that in my template's custom. css and a couple of other files, but this was the only way to remove that extra Caption as a "legend."