useSkill Sorcery Fireball getting stuck for 5-10 seconds on first fireball.

[czzplnm]

My bot will engage and during my sorc rotation it will use flamebolt 3 times. It does this fine, but when the creature is low on health it will get stuck for 5-10 seconds not doing anything.

                Skill skillFlamebolt = getSkill("Flamebolt");
                if (isSkillLearned(skillFlamebolt.id) && fireballCounter < 3)
                {
                    if (skillCooldown(skillFlamebolt) == 0)
                    {
                        Log("using flamebolt: fireball counter at: " + fireballCounter.ToString());
                        Thread.Sleep(timerDelay * 2);
                        UseSkill(skillFlamebolt.id);
                        fireballCounter++;
                        return;
                    }
                }

It logs: using flamebolt: fireball counter at: 0

Then gets stuck for 5-10 seconds and resumes. This code has worked fine for the past few days, but now it locks up. Why?

 

[Out]

NA servers?

 

[czzplnm]

NA servers?

Yes, it sometimes works fine though. It is weird. I can't stop it, nothing i do works. Is it a bug?