Error when decoding email subject (non-english)

Error when decoding email subject (non-english)

Sometimes ServiceDesk decode email subject not correctly and use it in request (for sample):

Прошу поменять номера телефонов 1272 и 1 =?koi8-r?B?Mjg5IM3F09TBzck=?=


But we sent this:
Прошу поменять номера телефонов 1272 и 1289 местами


When we try to change email encoding in Outlook, problem not gone:
FW: Прошу поменять номера телефонов 1272 =?windows-1251?B?IOggMTI4OSDs5fHy4Ozo?=

AND
FW: Прошу поменять номера =?utf-8?B?0YLQtdC70LXRhNC+0L3QvtCyIDEyNzIg0LggMTI4OSDQvNC10YHRgtCw0LzQuA==?=


But this happens only sometimes, and for now we cannot repeat this bug artificially.
Can you help me?


P.S. Sorry for my english...













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