diff --git a/lib/quo/query.rb b/lib/quo/query.rb
index de12103..fc8f21d 100644
--- a/lib/quo/query.rb
+++ b/lib/quo/query.rb
@@ -97,9 +97,9 @@ def first(limit = nil)
       if transform?
         res = query_with_logging.first(limit)
         if res.is_a? Array
-          res.map.with_index { |r, i| transformer.call(r, i) }
+          res.map.with_index { |r, i| transformer&.call(r, i) }
         elsif !res.nil?
-          transformer.call(query_with_logging.first(*args))
+          transformer&.call(query_with_logging.first(limit))
         end
       else
         query_with_logging.first(limit)
@@ -117,9 +117,9 @@ def last(limit = nil)
       if transform?
         res = query_with_logging.last(limit)
         if res.is_a? Array
-          res.map.with_index { |r, i| transformer.call(r, i) }
+          res.map.with_index { |r, i| transformer&.call(r, i) }
         elsif !res.nil?
-          transformer.call(query_with_logging.last(*args))
+          transformer&.call(res)
         end
       else
         query_with_logging.last(limit)
@@ -129,7 +129,7 @@ def last(limit = nil)
     # Convert to array
     def to_a
       arr = query_with_logging.to_a
-      transform? ? arr.map.with_index { |r, i| transformer.call(r, i) } : arr
+      transform? ? arr.map.with_index { |r, i| transformer&.call(r, i) } : arr
     end
 
     # Convert to EagerQuery, and load all data
@@ -226,7 +226,11 @@ def transformer
 
     def offset
       per_page = sanitised_page_size
-      page = current_page&.positive? ? current_page : 1
+      page = if current_page && current_page&.positive?
+        current_page
+      else
+        1
+      end
       per_page * (page - 1)
     end
 
diff --git a/lib/quo/results.rb b/lib/quo/results.rb
index bef3c9f..ed3e2f0 100644
--- a/lib/quo/results.rb
+++ b/lib/quo/results.rb
@@ -28,7 +28,7 @@ def group_by(&block)
       grouped = unwrapped.group_by do |*block_args|
         x = block_args.first
         transformed = transformer ? transformer.call(x) : x
-        block.call(transformed, *block_args[1..])
+        block ? block.call(transformed, *(block_args[1..] || [])) : transformed
       end
 
       grouped.tap do |groups|
diff --git a/lib/quo/utilities/callstack.rb b/lib/quo/utilities/callstack.rb
index a17e887..e81f4b2 100644
--- a/lib/quo/utilities/callstack.rb
+++ b/lib/quo/utilities/callstack.rb
@@ -12,7 +12,7 @@ def debug_callstack
         stack = Kernel.caller.grep_v(exclude).map { |l| l.gsub(working_dir + "/", "") }
         stack_to_display = stack[0..callstack_size]
         message = "\n[Query stack]: -> #{stack_to_display&.join("\n               &> ")}\n"
-        message += " (truncated to #{callstack_size} most recent)" if stack.size > callstack_size
+        message += " (truncated to #{callstack_size} most recent)" if callstack_size && stack.size > callstack_size
         Quo.configuration.logger&.info(message)
       end
     end