This is a bit of an obscure bug perhaps, but it is present on a number of sites I checked, running the latest pro 6.3.9 as well as earlier 6.2.5
When editing a text element newly added to the page, a span is added in certain circumstances around the last paragraph, with the following styling:
<span style="color: var(--c-base);">Text content...</span>
When the text element is added, if you create a paragraph break, then remove that paragraph break by putting the cursor to the end of the first paragraph and using delete, the text of the second paragraph has that span wrapped around it, and the color of the var(--c-base) overrides the text color set in the element options.
Here’s a video that demonstrates the process:
Doing various things to the text element before following the sequence above prevents it from happening, and it doesn’t always repeat after the first time.
Tested across two sites, one in current development on 6.3.9, and one built a while back, now on 6.2.5, and the same result occurred.
