Why pom-pom and Bofors production faced different problems

Did the two-pounder pom-pom suffer the same production problems as the 40 mm Bofors?

No; it had its own limitations, but decades of prior production removed many manufacturing problems that complicated rapid Bofors adoption.

The two-pounder pom-pom had its own problems, but decades of manufacture had given its producers time to resolve many of them before World War II. Its earlier barrel history is distinguished from the later firing mechanism, whose date is recalled uncertainly as about 1910. Bofors adoption involved adapting a Swedish design across British and American measurement conventions and production practices. The explanation offered here links some difficulties to drawing conversion and assumptions about how much fitting finished components required. Large American orders encouraged factories to prepare for mass production from the outset. British production also scaled up, so the difference concerns initial order size and industrial practice, without implying that only America could mass-produce.