These are two different requests. the articles are both urlencoded() in PHP. The first request will match but the second wouldn't probably because of the question mark (? or %3F); they both have the plus sign (+ or %2B)
Here is my .htaccess rule
RewriteRule ^article~([^.]+)$ web/news/article.php?article=$1
My requests:
1
article~The-best-Android-Wear-smartwatch%2B12
2
article~Google-Play-Store-not-working%3F-Here-are-some-possible-fixes%2B10
I suspected that the presence of a question mark (? or %3F) in the second request could prevent it from working as it generate error code 403 (Access forbidden!).