How to reproduce:

1. Create a new project
2. Create an Input Field
3. Set Content Type to Email Address
4. Enter play mode
5. Type anything with at least one dot

e.g. "aaa.aa.aaa."

6. Move the cursor after a dot (not the last one)

e.g. "aaa.|aa.aaa."
or
"aaa.aa.|aaa."

7. Try to insert more dots

Expected behavior: It's impossible to insert more than one dot in a row
Actual behavior: It's possible to insert any number of dots

Note: It only happens if cursor is beyond the dot but not ahead of it

Reproducible: 5.3.7p2, 5.4.3p3, 5.5.0p1, 5.6.0a6