UI does not report failed delete actions of attachments

I set the maximum Java memory size to 600M and I cannot delete the attachments larger than 4MB. Even though I get the "Attachment deleted" message, I also have the "java.lang.OutOfMemoryError: Java heap space" error in the logs (see the attached file).

Moreover, initially the attachment seems to have been deleted, but after a refresh it reappears in the list.