The answer to your question is "yes". Basically there are 3 problems with the 'pattern' brake parts for the 126 (500 brake shoes, made to the original 'factory' specification, made by Ferodo can be obtained form Middle Barton Garage)--(1) the lining material is fractionally thinner than original specs, (2) the friction washers on the 'self-adjusters' don't seem to have the same amount of grip that the originals had and, (3) the 'pattern' springs are slightly too short.
The answers to these problems are:--(1) use the best quality shoes that you can obtain--I use shoes made by "Metelli" with no problems, (2) the good quality shoes seem to have better friction washers and, (3) if possible, use the original 'factory' springs. If you can't, then stretch the 'pattern'springs by (if my memory serves me right) about 1/8th inch. If you have the 'factory' springs but don't wish/can't use them, stretch the new springs to match the length of the originals.
The problem is that the new springs, being shorter, are stretched more when you put your foot on the brake pedal and therefore put more 'return' tension into the spring. Couple this with slightly less 'grippy' friction washers and thinner linings and you have a brake operation problem