I think you will need to "update" the symbol library by re loading it, rigth click in a free area inside the library palette and choose reload library, then it will go back and check/ set the symbol to standard value ( all symbols in that folder )
When open, TC load it in to memory i guess, so it should go quicker for insert a symbol.
Or at least, in V 17 > 21, i dont know in V 12.5
V18, V19, V20, V21, 2015/ 16/ 17/ 18 Pro. Platinum
Deluxe V20, V21, 2015/ 16/ 17
Windows 10 Home Premium 64 bit, 32 GB
NVIDIA Geforce GTX 780m, 1 GB