diff --git a/demo/test_genotyping.vcf b/demo/test_genotyping.vcf
index 21e3a92..96c6d7e 100644
--- a/demo/test_genotyping.vcf
+++ b/demo/test_genotyping.vcf
@@ -1,5 +1,5 @@
 ##fileformat=VCFv4.2
-##fileDate=20230810
+##fileDate=20230823
 ##INFO=<ID=AF,Number=A,Type=Float,Description="Allele Frequency">
 ##INFO=<ID=UK,Number=1,Type=Integer,Description="Total number of unique kmers.">
 ##INFO=<ID=AK,Number=R,Type=Integer,Description="Number of unique kmers per allele. Will be -1 for alleles not covered by any input haplotype path">
@@ -10,7 +10,7 @@
 ##FORMAT=<ID=GL,Number=G,Type=Float,Description="Comma-separated log10-scaled genotype likelihoods for absent, heterozygous, homozygous.">
 ##FORMAT=<ID=KC,Number=1,Type=Float,Description="Local kmer coverage.">
 #CHROM	POS	ID	REF	ALT	QUAL	FILTER	INFO	FORMAT	sample
-chr1	15952	.	T	A	.	PASS	AF=0.208333;UK=62;MA=0	GT:GQ:GL:KC	0/1:79:-70.0138,-4.629e-09,-7.972:2
-chr1	16509	.	A	G	.	PASS	AF=0.416667;UK=62;MA=0	GT:GQ:GL:KC	0/1:10000:-34.6291,0,-78.37:3
-chr1	16636	.	T	TA,TAAA	.	PASS	AF=0.375,0.416667;UK=50;MA=0	GT:GQ:GL:KC	1/2:19:-45.0636,-36.96,-35.35,-5.135,-0.004514,-1.986:1
-chr1	18262	.	T	C	.	PASS	AF=0.916667;UK=62;MA=0	GT:GQ:GL:KC	1/1:10000:-127.447,-32.9,0:3
+chr1	15952	.	T	A	.	PASS	AF=0.208333;UK=62;MA=0	GT:GQ:GL:KC	0/1:54:-49.4011,-1.686e-06,-5.411:2
+chr1	16509	.	A	G	.	PASS	AF=0.416667;UK=62;MA=0	GT:GQ:GL:KC	0/1:10000:-29.5279,0,-49.28:3
+chr1	16636	.	T	TA,TAAA	.	PASS	AF=0.375,0.416667;UK=50;MA=0	GT:GQ:GL:KC	1/2:32:-31.7599,-25.35,-23.76,-4.596,-0.0002714,-3.222:1
+chr1	18262	.	T	C	.	PASS	AF=0.916667;UK=62;MA=0	GT:GQ:GL:KC	1/1:10000:-94.3729,-31.56,0:3
diff --git a/src/graphbuilder.cpp b/src/graphbuilder.cpp
index 982a958..4a98210 100644
--- a/src/graphbuilder.cpp
+++ b/src/graphbuilder.cpp
@@ -131,8 +131,9 @@ void GraphBuilder::construct_graph(std::string filename, FastaReader* fasta_read
 		current_start_pos -= 1;
 		// if variant is contained in previous one, skip it
 		if ((previous_chrom == current_chrom) && (current_start_pos < previous_end_pos)) {
-			cerr << "GraphBuilder: skip variant at " << current_chrom << ":" << current_start_pos << " since it is contained in a previous one."  << endl;
-			continue;
+			stringstream err_msg;
+			err_msg << "GraphBuilder: variant at " << current_chrom << ":" << current_start_pos << " overlaps previous one. VCF does not represent a pangenome graph."  << endl;
+			throw runtime_error(err_msg.str());
 		}
 
 		// get REF allele
diff --git a/src/pangenie-genotype.cpp b/src/pangenie-genotype.cpp
index 8d777e5..e2bd80e 100644
--- a/src/pangenie-genotype.cpp
+++ b/src/pangenie-genotype.cpp
@@ -16,7 +16,7 @@ int main(int argc, char* argv[]) {
 	cerr << endl;
 	cerr << "program: PanGenie - genotyping based on kmer-counting and known haplotype sequences." << endl;
 	cerr << "author: Jana Ebler" << endl << endl;
-	cerr << "version: v3.0.0" << endl;
+	cerr << "version: v3.0.1" << endl;
 
 	string reffile = "";
 	string vcffile = "";
@@ -31,7 +31,7 @@ int main(int argc, char* argv[]) {
 	bool only_genotyping = true;
 	bool only_phasing = false;
 	long double effective_N = 0.00001L;
-	long double regularization = 0.001L;
+	long double regularization = 0.01L;
 	bool count_only_graph = true;
 	bool ignore_imputed = false;
 	size_t sampling_size = 0;
diff --git a/src/pangenie-index.cpp b/src/pangenie-index.cpp
index cf0f45d..9e3b1d8 100644
--- a/src/pangenie-index.cpp
+++ b/src/pangenie-index.cpp
@@ -15,7 +15,7 @@ int main(int argc, char* argv[]) {
 	cerr << endl;
 	cerr << "program: PanGenie - genotyping based on kmer-counting and known haplotype sequences." << endl;
 	cerr << "author: Jana Ebler" << endl << endl;
-	cerr << "version: v3.0.0" << endl;
+	cerr << "version: v3.0.1" << endl;
 
 	string reffile = "";
 	string vcffile = "";
diff --git a/tests/GraphBuilderTest.cpp b/tests/GraphBuilderTest.cpp
index 13140ac..7a38ddb 100644
--- a/tests/GraphBuilderTest.cpp
+++ b/tests/GraphBuilderTest.cpp
@@ -283,9 +283,7 @@ TEST_CASE("GraphBuilder overlapping variants", "[GraphBuilder overlapping varian
 	string fasta = "../tests/data/small1.fa";
 
 	map<string, shared_ptr<Graph>> graph;
-	GraphBuilder(vcf, fasta, graph, "../tests/data/empty-segments.fa", 10, false);
-	// should have skipped variant that is contained in another
-	REQUIRE(graph.at("chrA")->size() == 1);
+	REQUIRE_THROWS(GraphBuilder(vcf, fasta, graph, "../tests/data/empty-segments.fa", 10, false));
 }
 
 TEST_CASE("GraphBuilder get_chromosomes", "[GraphBuilder get_chromosomes]") {