Long array NBT tags were not converting from NBT correctly, always coming to json as [1, 2, 3 ...] instead of the correct numbers. This release includes the fixed upstream nbt2json v0.4.1.
Please note: McpeTool does not know which keys are NBT and which aren't. Bedrock v1.16 introduced a new subchunk data version 8 which if fed to the nbt2json converter will usually give an NBT string tag error as it thinks the 8 is the start of a string tag, but block data keys are not in NBT format. McpeTool just tries to do what you tell it right now; it doesn't know which key types hold which data.