F2C Pro 6.11.0
Joomla 3.4.4

I have used F2C to set up several article creation options, with different content types, saved in different categories, and added several articles via the front-end forms. Then updated to Joomla 3.4.4.

After that I changed the text of an already created article (via F2C front-end created and edited) and suddenly the text appears in different sizes after saving.
The Joomla update probably has nothing to do with it, because if I add a new article the problem does not occur at first publishing and I had not adjusted the previously published articles before updating. So the problem starts with the adjusting of the articles and only in a certain content type (with editor field).

Previously I would find something like this in the joomla article (JAM) that was created by F2C:

<p>Text paragraph.</p>
<p>Text paragraph.</p>
<p>Text paragraph.</p>

But after adjusting the article I find something like this:

<p>Text paragraph.</p>
<p><span style="font-size: 12.16px; line-height: 1.3em;">Text paragraph.</span></p>
<p>Text paragraph.</p>

I tested this several times, both via filling the form in the back- and front-end, by clearing the content of the article and adding new text. It seems pretty random what happens; sometimes the result is as it should be, but most of the time the problem occurs. Tested different articles, several times. Problem is not related to length of text, using copy/paste or image added or not. However it does only occur in a content type with an Editor field.

By the way: no font size or line-height was/is available in the Editor in the F2C form on the front-end.

So I think the problem might be related to the ‘Multi-line text (editor)’ field or to the JCE editor, because I also tested some of the other content type forms again, were only ‘Single line text (textbox)’ and ‘Multi-line text (text area)’ are used, and the problem does not seem to occur in these forms.

Just for investigation purposes I also adjusted the Joomla article (JAM) directly by clearing it’s content and replacing it, only using JCE in wysiwyg mode. This gave a good result (no more font-size: 12.16px; line-height: 1.3em). Of course this is no solution, but it might give you an idea about where this problem may be located.
Also tried making a new content type with the same specifics (including the editor field again) and the same problem occurred again.

This is the F2C template for the article:

{$EDITOR}
{if $IMAGE}<img src="{$IMAGE}" alt="{$JOOMLA_TITLE}" style="margin-left: 20px; margin-bottom: 10px; border: 1px solid #3a0100; float: right;" />{/if}

Were {$EDITOR} stands for the Multi-line text (editor) field.

Articles were previously created using JCE 2.5.2, so when the problem first occurred (after upgrade to J 3.4.4.) I immediately updated JCE to the latest version (2.5.8) too, but that did not solve the problem.

Any idea what I’m doing wrong here?
Thanks in advance for your reply!