Recently atcoder implemented the same compilers for all its contests (blog post).

Now when you do a search for solutions with certain language (and compiler version) it will only show recent submissions because old submissions where made using a different version of the compiler. This makes looking for submissions harder, this is not a problem for problems with enough solutions but it is a problem for languages with few solutions, for example haskell which now shows almost no solutions for some problems. (there are solutions but they were submitted with a different compiler version that's why they are not showing in the results)