Segmentation fault in conformer search with constraints

[Jaebeom-P]

Describe the bug
Seems similar to issues reported in #458 and #417, I encounter "Segmentation fault - invalid memory reference" as attached.

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0  0x14b74b23ebef in ???
#1  0x5612977c6773 in get_xtb_constraint_block
	at /usr/local/src/conda/crest-3.0.2/src/parsing/parse_xtbinput.f90:142
#2  0x5612977c6773 in __parse_xtbinput_MOD_parse_xtb_inputfile
	at /usr/local/src/conda/crest-3.0.2/src/parsing/parse_xtbinput.f90:86
#3  0x56129769e950 in parserc2_
	at /usr/local/src/conda/crest-3.0.2/src/confparse.f90:2290
#4  0x5612976aabb0 in parseflags_
	at /usr/local/src/conda/crest-3.0.2/src/confparse.f90:2091
#5  0x561297328074 in crest
	at /usr/local/src/conda/crest-3.0.2/src/crest_main.f90:56
#6  0x5612973272b0 in main
	at /usr/local/src/conda/crest-3.0.2/src/crest_main.f90:26
/var/spool/slurmd/job1686226/slurm_script: line 21: 12775 Segmentation fault      (core dumped) crest mol.xyz --cinp .xcontrol.sample --gfn2 --alpb water --chrg 0 --notopo --noreftopo

To Reproduce
I try to run constrained conformer search. Hence, I initially run crest mol.xyz --contrain 1-2 to manually generate constraints file (i.e., .xcontrol.sample), then run constrained conformer search algorithm by crest mol.xyz --cinp .xcontrol.sample --gfn2 --alpb water --chrg 0 --notopo --noreftopo, but it failed.

I found that it can be resolved by simply changing the name of automatically generated constraints file, ".xcontrol.sample" to "constraints.inp", then it worked well. However, I still can't figure out the cause of this error.

I'm currently using the latest version, crest 3.0.2 and xtb 6.7.1

Expected behavior
A clear and concise description of what you expected to happen.