It's probably the single-letter article "a" that's causing the weird search result. It seems like diacritical letters are "flattened" into the plain English 26-letter alphabet. Normally common small words like "a", "the", "or", "and", etc. are filtered out by search algorithms, but the letter Å is a special case that's like a monkey wrench thrown into the search engine.
It's obviously a bug in the forum software.