Yeah, that gluey paste thing is so common with brown lentils. I read somewhere they just keep drinking up liquid forever if you let them. My trick is to start with way more broth than it seems like you need, like almost double what the recipe says, and keep a kettle of hot water nearby to top it up as it cooks. Also, adding a splash of vinegar or lemon juice at the end brightens everything back up if you have to water it down.

My buddy who does HVAC had a similar thing last winter. He was replacing a thermostat for this couple, and the husband followed him around asking why each wire went to a certain terminal. My friend spent an extra twenty minutes just drawing a little diagram on a notepad. The guy sent a photo of that drawing a month later when the wife was worried about the fan not turning on, and they fixed it themselves. He said it made him feel like a teacher, not just a repair guy.