This is actually three different bugs:

1) Given a set of scaling blocks with the RECT shape, RECT blocks of size 1 are permanently encrypted and unavailable in the upgrades menu. RECT blocks of size 2 are unlockable, and unlocking them also unlocks size 1 RECT blocks. However, upon exiting reloading, RECT blocks of size 2 and size 1 are once again locked. In the build menu, I cannot shrink RECT blocks of size 2 down to size 1, even if I receive no error saying I've got encrypted blocks. This error persists even if th'e starting vessel has size 1 RECT blocks, size 2 RECT blocks, or both. As far as I can tell, this error doesn't happen for any other block shape. My workaround is to replace the RECT block of scale 1 with a RECT_QUARTER block of scale 4. They're identical, or close to it.

2) Given a set of scaling ISOTRI_36 and ISOTRI_25 blocks with identical properties, an ISOTRI_25 will transform into an ISOTRI_36 when I attempt to scale it down. I have found this also occurs for ISOTRI_13 becoming ISOTRI_25 and ISOTRI_72 turning into ISOTRI_80. The workaround is to change some small detail between scaling sets, such as adding an additional space after the name in the ISOTRI_25.

3) If an ISOTRI_3 block's density is 1.0(at least; haven't explored this error) or less, the block will not appear. In tee Sandbox mode, with given a palette that includes it, there is an empty space in that spot. Addiontally, I receive an "Mass must be positive and non-zero" error when I load the palette that contains it. I've double-checked, and the block's density is definitely a non-negative, non-zero value. If I shrink a ISOTRI_3 block's scale to 1, it disappears. I'm not really sure of a workaround for this one, besides increasing the density maybe?

Discovered a new one!

4) I haven't tested all the possible combinations, but there is something wrong with RECT_ROOT. So far as I can tell, RECT_ROOT blocks can ONLY be launched from RECT_LAUNCHER1 (not RECT_LAUNCHER) or SQUARE_LAUNCHER blocks.

1&2, check your block.lua file ,the series blocks should keeps same state data,
or you may share the mod here , i may check it later.

3, the block cant set below 1 mass , so you should keep the size*density=mass >1
also ,the ISOTRI_3 shape may cause serious blueprint broken , due to ports near the tip are too close against each others , avoid this shape as much as you can

4, for default launcher set , [GEM_LAUNCHER\HEPTAGON_LAUNCHER\SQUARE_LAUNCHER] are radial launcher , the else is non-radial launcher (only straight shoot forward ),
as non-radial launcher with side launch_out port as RECT_LAUNCHER ,can only capable with shape has missile port on the side (like MISSILE shape) .

so you can see the mod example here : https://steamcommunity.com/sharedfiles/ ... =916026798

Well . . . these are still bugs that should be fixed for the most part, so I'm reporting them.

It's been a few updates, and ISOTRI_3 is still buggy. Perhaps if the game new to increase it's exactness/approximate more accurately for components whose vertices are very close to each other?

Also,
5) ISOTRI_6 is NOT a 6-degree isosceles triangle. If you make a circle from blocks of the ISOTRI_6 shape, you will find that while they *do* form a complete circle, they are made from 56 pieces, if I recall correctly. A circle radially divided into 6-degree segments should have 60 pieces. So yeah, fix please. My workaround is to incorporate a TRUE 6-degree triangle into my shapes.lua when modding, but I shouldn't have to do this.