Some last minute changes to work is causing me to consider the following trip

already started itinerary

XXX - Home
Home - XXX

new itinerary inserted into the first
YYY - Home
Home - YYY

I know that if XXX=YYY this would be back-to-back ticketing or nesting of same city pairs which is not allowed. If XXX and YYY were in different parts of the country, I should be fine but in my case the two cities are less than 150 miles apart. Will United have a problem with this?

Thanks