Joined: Jan 2010
Posts: 9,809
Likes: 1,784
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
It is possible that the expected bond line between cap and stay doesn't exist, and that the external blobs are holding things together.
That is one possibility with such hasty or unskilled workers having built or repaired this frame.
Might be best to merely reduce the thickness of the blobs to a uniform thickness instead of filing them away and finding little else holding the cap in place.