Laundry room smells like rotten eggs - Whirlpool Duet GHW9150P Front Load Washer

I too am so frustrated I can’t stand it! My ELECTRIC dryer smells like sulfur or rotten eggs, every so often. The clothes smell super fresh coming out of the washing machine and going into the dryer. They don’t actually smell bad when they come out of the dryer but the entire laundry room and downstairs will smell so overpowering at times, I don’t know what to do. The other day I hadn’t done laundry in two days. I took a blanket, spritzed it with febreeze and stuck it in the dryer just to freshen and remove some linen cupboard markings and the smell was horrendous. Once again, the blanket came out smelling okay thankfully but while that dryer is running, it will knock you over. The worst of it is, sometimes it won't do it for a month and then without warning, the next 4-5 loads set it off again. PLEASE HELPPPPP! We have had the dryer vent person come out and clean all the lines from the dryer to the outside. He said they were remarkably clean (but I clean the lint collector every single time I use it).

Does the sewer drain line have a trap at the bottom that prevents sewer gas from entering the room? If the smell seems to be coming from the washer itself, run a wash cycle empty with a cup of baking soda, detergent and hot water to clean the interior.