Be interesting to see if there any drain holes drilled down through the bottom rail, in the rebate, under the glass, leading to outside, or even, has the bottom inside bead got a gap underneath, which would suggest to me the door was hung the wrong way round. plus, I've never been convinced by just using "glazing tape" and always do a cap & seal solution as
@imageel has done, that's If the glass & rebate isn't going to be ventilated, which it can't be if its on the inside.
Fairly standard practice now, apparently its called "engineered" timber, I've seen it with more than 4 and then facing skins over all of it!!
DG units will have no warranty if bedded with linseed oil putty.
@JoeS sorry to say this but have left it for 7 years, so there is always consequence.
