I cannot reproduce your problem!
I tried several ways including going via the menus. Also tried various sub cats and still oK.
When you say
When connected, the display is OK
what do you mean by connected? Is it when logged in?
Could you advise which version of Joomla!, and version of jD please.
Do you know which browser is being used and on what OS? I t was OK for me on Firefox, Chrome and Edge
Also which Categories layout and Category layout are you using?
I see that the layouts you are using are <table based layouts which were used in the jD2.5 series, the latest layouts use <div structure through out.