There is a bug in the plugin. On line 83 and forward it says

else {
// this is a serialized array/object so we should NOT display it
--$count;
return;
}

That breaks the display of comment meta if it comes across a serialized object/array. It should just jump to the next in the loop, with continue instead of return, like:

else {
// this is a serialized array/object so we should NOT display it
--$count;
continue;
}

https://www.ads-software.com/extend/plugins/comment-meta-display/