The minimum connection time for those flights is 40 minutes.

This is how the MCT is determined at IAH - your flights fall under the 40 minute time period because of the flight number.

STANDARD.D/D...D/I...I/D...I/I.
ONLINE .45 1.00 1.00 1.15
OFFLINE .45 1.00 1.00 1.15
** OR * ARE ALL
UA-UA DD SUP FLT 1 - 9999 - FLT 1 - 9999
CANADA - CANADA
UA-UA DD .30 FLT 1 - 199 - FLT 1 - 199
UA-UA DD .45 FLT 1 - 199 - FLT 200 - 999
UA-UA DD .30 FLT 1 - 199 - FLT 1000 - 1744
UA-UA DD 1.00 FLT 1 - 199 - FLT 1900 - 3249
UA-UA DD .45 FLT 1 - 199 - FLT 3250 - 3969
UA-UA DD .40 FLT 1 - 199 - FLT 3970 - 5269
UA-UA DD .45 FLT 1 - 199 - FLT 5270 - 6539
UA-UA DD .30 FLT 1 - 199 - FLT 8015 - 8714
UA-UA DD .45 FLT 200 - 999 - FLT 1 - 199
UA-UA DD .45 FLT 200 - 999 - FLT 1000 - 1744
UA-UA DD .45 FLT 200 - 999 - FLT 3970 - 5269
UA-UA DD .30 FLT 1000 - 1744 - FLT 1 - 199
UA-UA DD .45 FLT 1000 - 1744 - FLT 200 - 999 ‡