Grout immediately darkened after regrout

[scg1889]

hi all. I've recently regrouted part of my bathroom floor as the grout had gone a bit dark and grubby in places. I wasn't sure whether it had darkened as there was a slow leak somewhere as it seemed to have deteriorated quite quickly or if it was just age (>10 years). Pic1 shows how it was before i regrouted. I used Mapei Flexible Wall & Floor Grout Beige which i'd used in a different part of the bathroom before and its maintained its original colour. however the new grout i've put down has very quickly darkened, although not uniform, it's patchy in places. Pic 2 shows similar area now post regrout. Additionally when i was raking it out the light colour underneath very quickly went dark in patches, like within a couple of mins, so a bit worries there could be some dampness underneath (pic3 is after it was raked). The final picture shows where some areas are light - the colour it should be alongside some of the dark patches. The areas next to the bath and sink are actually still maintaining the beige colour so i don't think there's a leak there, it is dark closer to the toilet though when we had a leak from the toilet a couple of years back i left gaps in the sealant so we'd know if it happened again and it's fine around there. I did mix by hand rather than electric given it was such a small area, i would say it was probably a bit wetter than i expected when I applied it, though i did actually use a little more powder to water ratio than the instructions stated. It's only my 3rd go at regrouting so is it poor mixing/applying or do people think the darkening could be due to a leak under the surface somewhere? TIA

1Before.jpg (168.26 KiB) Viewed 608 times

2After.jpg (152.39 KiB) Viewed 608 times

3Rake.jpg (95.35 KiB) Viewed 608 times

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