I have several snippet and have found that the usage is not consistent, the main problem I've been seeing is while I continue typing after inserting a snippet keyword only part of the snippet is fully replaced. For example my keyword is ;cc to insert the word Comcast. If I'm typing quickly I'll see the following happen ; Comcast where the expansion of the snippet is leaving the semi colon from the keyword behind.
MBP 2.8 i7 16GB ram
OSX 10.10.5
Alfred 3 with Power Pack v3 [652]
Let me know what else I can provide you, I'm not seeing any errors in the Console for Alfred.