It's actually drawing specific. So, I think that it has to do with a UCS and a DVT. Probably not an issue that most designers run into. It may not be a best practices method of getting some things done.
Bro, How AutoCADdy of you. That would work for solid filled blocks, but not for those without solid fills (Backflow Preventers, Master Valves and Flow Sensors, etc). BTW, you, be and Greg R need to grab a beer together some time soon.
Thanks Jer. Instead of connecting the mainline to the elements, I tried first drawing the mainline and then plugging the elements in. It looks like something funny is going on. But it's better and I can't deal with it now. Submittal is due. Thanks for your consideration though.
Usually this is due to having customized blocks that are using unusual elements, other than lines and polylines. But these all look like stock symbols. So my next hunch is that those blocks are not at 0 elevation. Beyond that, we'd need the drawing.