[Sideband]

My take on it is this...Murphy would not have sold an unstable set! It's very likely that when the set was new and those decouplers were in first-class condition, it wasn't unstable since the capacitors at that time were able to bypass any RF that crept into the I.F stages. As the set aged, the ESR went up (maybe only after a few years) causing instability or maybe some sets were only marginal, bordering on instability and after only a short while were going unstable. This resulted in Murphy adding the .04 as an additional RF filter in later production to avoid nuisance failures.