I said that it stuck it to a glass window, did you stick it on the bulletin first? This type is sticky with the sticker attached first, then the side you pasted from it is written on the item description (manufacturer) that it can be replaced. If you paste the tape on the glass first, the adhesion of the poster will be weak. So it may have fallen. Moreover, the glass surface is easy to condense, it is not suitable for sticky objects.
I pasted a 600 x 600 mm size poster made from woodfree paper on a windowpane and it peeled in less than an hour. The tape remained on the glass surface and only the poster peeled off, so it seems that the weight of the paper is the cause. I used a "peel off" type as it is to be replaced every month, but it did not become usable. Application seems to be limited.