now tonight it's lagged again until the file is fully-uploaded. I got tired of waiting the usual 10 seconds and moved it to its own directory and linked that (instantly works). Then several minutes later while doing something else I started getting popups from my systray that it was copying links now that it was finally done uploading.
For me the link sometimes copies at random now on large files too – not when I choose copy link to clipboard and not only once the file is fully uploaded but more like in the middle. Also, submitting the share dialog while the file was uploading didn't fail but was not send to to the email address either even after the upload finished!