Tested this in several pools and everything is ok again. Also NPC sims use the pools as they should. Thank you for this!!!!
Does this happen in any pool, or only on that specific lot? Try testing out on other lots with pools and see if it's related to all swimming codes or simply a glitchy pool on a lot.
I've tried it on 4 different lots and it happens for all of them.
I don't think there's a work around at this point
For me it mostly happened in corners.
Added
Unfortunately, this bug is far worse. NPC sims don't use the pool at all any more in public venues. It stays completely empty. "Swim here" is also broken and works only with very short distances - otherwise the sim will leave the pool and jump back in at the wanted place. It seems that routing on water is completely broken.
For me, it's in any pool on any lot, including the preset ones in Windenberg (the public pool and the gym one). I have all the packs, but no mods. It's been doing this since the toddler update, if I'm not mistaken.
I'm getting this too. It was fine until I installed some new packs and since then they swim for about 2 seconds then just get out the pool, seems a bit of a waste of time having one now.
Edited to add: It don't seem to get my sims to stay in the pool regardless of the action - energised laps, any laps, swim playfully, none of it works, it seems that none of them like the water! Even if I direct them to "swim here" most of the time they will get out the pool and walk to the spot, or walk to as close as they can, then drop in the pool, swim to the spot then get out. Really annoying.
Tested this in several pools and everything is ok again. Also NPC sims use the pools as they should. Thank you for this!!!!
