Yes, it's well known that PMC has had their share of quality control problems with both ammunition and empty brass.
The South Korean Poonsang Metallic Corporation ammunition factory was set up by either Winchester or Remington technical assistance in the mid-to-late 1970's. Since then, they've developed a more or less good reputation for military small arms ammunition production (for the South Korean military) and throughout asia. For US sales, they are not quite as popular as the Big Three (Winchester, Remington, or Federal).
PMC has had issues with improper neck annealing, dimensional standards, and serious quality problems (too much powder/wrong powder), etc and several product recall notices in the last 30 years. However, in defence of PMC, all of these have at at one time or another, also been problems with the American Big Three.
I've used many thousands of pistol caliber cartridges and cases, and had no problems. Other users have described to me similar problems in rifle calibers (loose primer pockets, cracked necks, difficulty chambering and extracting, etc. Who knows? Maybe you just get an occasional bad batch.