Process ticket - Owner is changed automatically on ticket forward

[aph]

Could someone explain me the logic as to under which conditions the ticket owner is changed on ticket forward? The scenario is as follows:
1) A process ticket is generated in OTRS on e-mail receipt. The owner as well as responsible is Admin OTRS
2) Agent A checks the ticket and sets agent B as owner and himself as responsible
3) Agent A then forwards this ticket to an external e-mail address.

At this point the owner is automatically changed to Agent A (one who forwarded the ticket). I would have guessed this happens because agent A actually handled the ticket, but that does not explain what happens when the ticket is forwarded the second time. This goes as follows:
1) Agent A sets agent B as owner and himself as responsible again.
2) Agent A then forwards the ticket to an external e-mail address

At this point the owner is not changed to agent A (agent B stays owner, and agent A the responsible) although she forwarded the ticket just as in the first instance.

Why does the behaviour differ when a ticket is forwarded the first time from when it is forwarded the second time?

[aph]

Any ideas on this one?