When using the above to get the creative tab ids there are many tabs that are missing from the output.

• NuclearCraft
• Recurrent Complex
• TeaStory
• EnderIO
• Netherending Ores
• Pixelmon
• Spartan Shields
• Extra Alchemy
• Extra Cells 2
• Enderman Evolution

Means they don't exist when ContentTweaker runs. Generally when creating items you should either put them in MC tabs or in a custom ContentTweaker tab