Yes, Merrilliana has a frequnet problem with small pots, as it has a very long and narrow root system, sorta like 1 giant tap root only made up of like 50+ Nepenthes roots. The reason lots of people have trouble with Merrilliana is because they don't know that Merrilliana likes a very deep not wide pot to extend it's roots into. If not given this extra deepness it will not do well and cease pitcher production first, then leaves will form very wavy,stunted,and deformed as a sign it is very rootbound. I will transplant my Merrilliana about every 3 years, I check the roots and if they are coming in close proximity to the pot bottom I transplant, but it has proven very easy to grow with true lowland conditions and very high humidity and I reccomend planting in Long fiber spahgnum with lots of perlite and quit abit of orchid bark, it is a VERY airy and super fast drianing mix that my merrilliana love. But just keep it in a deep pot with long fiber sphangum, I don't like peat and perlite as it is too heavy and not light and airy enough for the roots. BUT you can use it with succes, long fiber spahgnum also makes VERY easy transplanting and virtually no rot distubance if you transplant carefully.