Whole Weat Starter Smells Off
So I have a WW starter going with 100% hydration that is a little over a month old. I have been feeding it twice daily for about 3 weeks give or take a few days where I was only able to feed once daily. It doubles in size within 4 hours. Just recently I have noticed that before my feedings, it smells somewhat like feet. I know it's a weird comparison but that is what I got. No mold or funky color to it just a weird smell. I have kept this starter at room temp since it was created. Any suggestions as to what it could be and is this starter safe to use, etc. I have an AP flour that I have used but not the WW one yet.