2 days ago, I was able to ask a very nice CIC call center agent about this (my line is also still missing...).
He told me it is normal, because of a system update (after the new law came in force). For people who applied before the new law and who already had activity on Ecas, Lines can appear and desappear, without any effect on their application.
People you see with a Transfer line are people whose files has JUST been transfered to LO. So when the Local Office agent updated their files (under the new system), their Transfer line appeared...
I understood that our "transfer line" will not reappear until an agent updates our file with a new status / activity (test invitation, oath, ..)
Some people will never see their Transfer Line back, and it is normal.
So, dont worry !