I would like to know what I did wrong

Bead and cove ,on the face of it(pun not intended),seems like a great idea.I have never used it.Keeping joints well clamped whilst the glue sets is still needed but may not be apparent as it may be difficult to see the need in all locations.The detail could hide voids that get discovered when the good looking surface is removed.
The strength of your"blemishes" is not too critical as the glass either side with the resin soaking in will lock the combination together.
Bevelling strip joints can also result in the same issue but allows for immediate and easier visual inspection and early remedy resulting in better "process control".
All the best, from Paul.