I ran a GEDmatch multi-kit analysis and got this report:

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And putting a different kit in first position, I get this report:

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The strange thing I notice is on Chromosome 12, in the first report I get several matches that span as much as from 1,359,590 to 5,316,226 (about 12.3 cM). In the second report, I get from 1,517,192 to 3,941,530 (7.58692 cM) matching .

It matches from first report, so why doesn't appear in the first report? Is this a bug?