Micro joint infill on top of grout ? - Tile Advice

[LozWales]

Hi tiler has used micro joint infill in few places to reduce stress (decoupling matting also used) - before putting in the gap between tiles put grout in to stop the infill resin running away - doesn’t that defeat purpose of the in fill ? As it happens used way too much resin and had overspill each side of line and whatever I did still looked a poor job so removed the resin and going to do it myself but can see quite a bit of grout was used before job done so in fill will only be a few mm deep - is this a problem - should I be trying to scrape grout out as well - be a nightmare job as 25 metres of infill and bad enough getting the cured infill out ? Any advice greatly appreciated, Loz