Further details of the Teijin press release can be found here:
https://www.compositesworld.com/new...-supplies-exterior-body-panels-to-lotus-emira
Note a different process is used to produce the rear panels/tailgate vs the doors and rear quarter panels.
Reading this article I was intrigued by the use of calcium carbonate in the composite mix (to improve its mechanical properties). However this additive could potentially play a role in the formation of paint bubbles.
Firstly, I do have a chemistry background and some knowledge of polymers - but the following is just a possible explanation - not proven fact!
Polyester resin (of the type often used in the production of glass fibre composites) is commonly formed by reaction of ethylene glycol with maleic anhydride (itself produced by dehydration of maleic acid) to produce an unsaturated polyester resin. This is is commonly dissolved in styrene to form a viscous resin solution. The unsaturated polyester resin/styrene mix is cured by addition of a free radical initiator (e.g. a peroxide) to produce a solid, 3-dimensional resin. If the maleic anhydride was not sufficiently pure or polyester resin synthesis or curing was not properly controlled, then the resulting cured resin could contain acidic compounds (e.g. maleic acid). Also, some fire retardants sometimes used in the production of composites are also acidic. After water penetration (e.g. rain water or condensation running down an improperly sealed inner surface of a Emira door) these acidic compounds could be mobilised within the resin and interact with the calcium carbonate particles. The end result would be the generation of CO2 within the resin composite. Over time the internal pressure will increase and eventually gas will escape through microfissures to the surface - resulting in a paint bubble!
IF this is the source of the paint bubbles, their occurrence will be somewhat random as dependent on several variables such as batch-batch variation of the resin used, how well controlled the curing process is, how well sealed the inside of the panels are, extent of water exposure/water ingress, etc. It would unlikely be affected by the type of pigment (colour) used in the paint mix.
Again, IF this is the explanation for the formation of paint bubbles, preventative measures could include replacement panels made using different inorganic particles that do not react with acids (e.g. calcium fluoride) or better sealing to prevent water ingress. There has been some speculation that a different internal coating is used on later doors. The only way to treat an existing door and prevent the formation of new bubbles would be to completely dry the door (in a vacuum oven) and completely seal the inner surface to prevent any new ingress of water.
All of this is somewhat ironic given the reason Lotus used Teijin panels was: “This treatment technology results in a more robust resin mix making molded parts more resistant to handling damage, preventing micro-cracks that cause paint pops, pits and blistering, and improving paint adhesion and bonding characteristics.”