Not sure how to explain it, but after all those latest plugin and WordPress itself updates it looks like 'span.wpcf7-form-control-wrap' needs a set width, otherwise after clicking submit without filling required fields, some fields get different widths.
I've noticed that on few websites of ours already.
You can see what I mean if you go for example to http://www.apexfire.ie/contact-us/ and click on submit button without filling the fields.
Now, I already fixed it by setting width to 100%, but if you inspect span.wpcf7-form-control-wrap styling and disable 'width: 100%;' you will see the issue.
Other example would be http://www.fivestarcleaning.ie/contact-us/ where I had to set max-width for 'span.wpcf7-form-control-wrap' - same like other example you have to inspect it and disable to see differences.
Also I've noticed styling problems with 'select option', different widths depending on chosen/not chosen option - and funny enough it's also related to 'span.wpcf7-form-control-wrap' styling, again looks like it needs a width being set in css.
What am I missing or what am I doing wrong?