I noticed an inconsistency for the determined result combinations. For example, why is the maximum vertical support reaction of RC4 zero? In my clear system, I can easily see that this cannot be true. The minimum load is alright.
As the support forces for the RCs 1 - 3 act in the same direction, the result in RC4 is for each only one value and the other value is zero.
To solve this problem, you have to define the other RCs in the result combination 4 as "permanent": RC4 = RC1/permanent or RC2/permanent or RC3/permanent.
In this way, the result combinations 1 to 3 will be compared among each other as permanent. The most unfavorable acting value provides the result.