Just checked again by removing the line 6 override. When I remove the override, line 6 reverts to $3,550 even though family coverage has been chosen and line 5 shows $7,100 as it should. So the default doesn't work to generate the married limit ($7,100) on line 6 (form 8889) even though "family" is checked at the top of the form and $7100 is shown on line 5.

Line 6 defaults to $3,550 even though line 5 is $7,100. The over-contribution then generates form 5329 and a 6% penalty on the excess contribution over $3550.

Note this is a Married Filing Separate issue. If MFJ was used, the default becomes $7100 and there's no problem.

I'm wanted to check with the community to see if $7100 is allowed on line 6 in this situation.

I'll have to say your answer is incorrect unless there's another way to do it that doesn't require entering data in the override field for line 6.