Causing problem to W3TC plugin feature

I am experiencing the same issue. Tweetily breaks the functionality of W3 Total Cache and renders it useless as a caching plugin (at least for Page Cache and Minify). I’m fairly this is caused by the following function in top-core.php (line 7), which gets required by tweetily.php (and therefore is run on every page load):

if ( function_exists('w3tc_pgcache_flush') ) {
w3tc_pgcache_flush();
w3tc_dbcache_flush();
w3tc_minify_flush();
w3tc_objectcache_flush();
$cache = ' and W3TC Caches cleared';
}

This flushes the W3TC cache every time a page is loaded, which then makes the caching feature of W3TC absolutely worthless. I also found that it caused errors uploading minified JS and CSS because the minified files were being flushed before they could be uploaded to the CDN.

I saw that there was a fix for tweet flooding with W3TC in the changelog for a previous version of Tweetily, but in my mind it is not a fix if it simply removes the core functionality of another plugin. At the very least warn W3TC users that they won’t be able to use Page Cache or Minification if they enable this plugin.

Are you running version 4.0? Try re-installing, de-authorizing your Twitter account, then authorizing it again and resetting the settings for a fresh install.