Why are مَدْخَلٌ and مَكْذُوبٌ not on the same template?

Noun Patterns: Jāmid, Maṣdar, Mushtaq and 50 Basic-Triliteral Maṣdar Entries

• They differ only in meaning, not pattern
• They share mīm but their remaining templates differ
• One is a noun and the other a particle
• They have exactly the same root