I have a list with few workflows. After adding a new one (now I have 8 workflows on one list) I noticed some problems. When some tasks are assigned they have status: "not started" and when user try to complete one, it shows error: "This task is currently locked by a running workflow and cannot be edited". Tasks after some time change status to "in progress" and can be completed. However it sometimes take more than hour.
After few tries I noticed that problem is only then, when before task there is an additional send email action (moreover before every task there is an email with link to task). So my question is: What cause my problems and such a delay? Is it possible that sending email so much slow down workflow? It is also a little strange because I get emails very fast...
