Alright after a bit of searching I'm now SURE this problem is not heRO specific; there a dozens of threads describing the same problem exactly as you have. Most have no solution. One or two have recommended patching up iRO and Sakray and have thereafter posted that the problem disappears with an updated client. But it apparently needs further confirmation.
Some questions on this...
Should iRO be patched BEFORE installing heRO lite? And if not
After patching iRO and Sakray is it necessary to re-install\patch heRO again?
@2cat
I use no-Death frequently and have not experienced this problem so I'm unsure if no-Death could be the cause. However considering the mass of threads outlining this exact problem it seems unlikely. Infact I have never had this problem here on HeRO. The mind boggles @_@. It seems definitely to be client-side though.
The struggle to free myself of restraints becomes my very shackles. - Meshuggah