Here is my opinion, for 'iso_intersection_small' 
not sure what the problem is, but your geometry in some places look like this ... think about how to arrange it, i.e. the problem is most likely the length of coordinate values, for example ...
```
(4 row)
2.24052434999272 48.633728,
2.2494507 48.633728,
2.2515106 48.6344147,
2.25202558437494 48.633728,
(6 row) 
2.3648071 48.5733032,
2.36618038333414 48.5733032
(7 row)
2.42197043750091 48.6472892624991, 
...etc.
```